Generic Operating System Services
*********************************

The modules described in this chapter provide interfaces to operating
system features that are available on (almost) all operating systems,
such as files and a clock.  The interfaces are generally modeled after
the Unix or C interfaces, but they are available on most other systems
as well.  Here’s an overview:

* "os" — Miscellaneous operating system interfaces

  * File Names, Command Line Arguments, and Environment Variables

  * Python UTF-8 Mode

  * Process Parameters

  * File Object Creation

  * File Descriptor Operations

    * Querying the size of a terminal

    * Inheritance of File Descriptors

  * Files and Directories

    * Linux extended attributes

  * Process Management

  * Interface to the scheduler

  * Miscellaneous System Information

  * Random numbers

* "io" — Core tools for working with streams

  * Overview

    * Text I/O

    * Binary I/O

    * Raw I/O

  * Text Encoding

    * Opt-in EncodingWarning

  * High-level Module Interface

  * Class hierarchy

    * I/O Base Classes

    * Raw File I/O

    * Buffered Streams

    * Text I/O

  * Performance

    * Binary I/O

    * Text I/O

    * Multi-threading

    * Reentrancy

* "time" — Time access and conversions

  * Functions

  * Clock ID Constants

  * Timezone Constants

* "argparse" — Parser for command-line options, arguments and sub-
  commands

  * Core Functionality

  * Quick Links for add_argument()

  * Example

    * Creating a parser

    * Adding arguments

    * Parsing arguments

  * ArgumentParser objects

    * prog

    * usage

    * description

    * epilog

    * parents

    * formatter_class

    * prefix_chars

    * fromfile_prefix_chars

    * argument_default

    * allow_abbrev

    * conflict_handler

    * add_help

    * exit_on_error

  * The add_argument() method

    * name or flags

    * action

    * nargs

    * const

    * default

    * type

    * choices

    * required

    * help

    * metavar

    * dest

    * Action classes

  * The parse_args() method

    * Option value syntax

    * Invalid arguments

    * Arguments containing "-"

    * Argument abbreviations (prefix matching)

    * Beyond "sys.argv"

    * The Namespace object

  * Other utilities

    * Sub-commands

    * FileType objects

    * Argument groups

    * Mutual exclusion

    * Parser defaults

    * Printing help

    * Partial parsing

    * Customizing file parsing

    * Exiting methods

    * Intermixed parsing

  * Upgrading optparse code

  * Exceptions

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

* "logging" — Logging facility for Python

  * Logger Objects

  * Logging Levels

  * Handler Objects

  * Formatter Objects

  * Filter Objects

  * LogRecord Objects

  * LogRecord attributes

  * LoggerAdapter Objects

  * Thread Safety

  * Module-Level Functions

  * Module-Level Attributes

  * Integration with the warnings module

* "logging.config" — Logging configuration

  * Configuration functions

  * Security considerations

  * Configuration dictionary schema

    * Dictionary Schema Details

    * Incremental Configuration

    * Object connections

    * User-defined objects

    * Handler configuration order

    * Access to external objects

    * Access to internal objects

    * Import resolution and custom importers

  * Configuration file format

* "logging.handlers" — Logging handlers

  * StreamHandler

  * FileHandler

  * NullHandler

  * WatchedFileHandler

  * BaseRotatingHandler

  * RotatingFileHandler

  * TimedRotatingFileHandler

  * SocketHandler

  * DatagramHandler

  * SysLogHandler

  * NTEventLogHandler

  * SMTPHandler

  * MemoryHandler

  * HTTPHandler

  * QueueHandler

  * QueueListener

* "getpass" — Portable password input

* "curses" — Terminal handling for character-cell displays

  * Functions

  * Window Objects

  * Constants

* "curses.textpad" — Text input widget for curses programs

  * Textbox objects

* "curses.ascii" — Utilities for ASCII characters

* "curses.panel" — A panel stack extension for curses

  * Functions

  * Panel Objects

* "platform" —  Access to underlying platform’s identifying data

  * Cross Platform

  * Java Platform

  * Windows Platform

  * macOS Platform

  * Unix Platforms

  * Linux Platforms

* "errno" — Standard errno system symbols

* "ctypes" — A foreign function library for Python

  * ctypes tutorial

    * Loading dynamic link libraries

    * Accessing functions from loaded dlls

    * Calling functions

    * Fundamental data types

    * Calling functions, continued

    * Calling variadic functions

    * Calling functions with your own custom data types

    * Specifying the required argument types (function prototypes)

    * Return types

    * Passing pointers (or: passing parameters by reference)

    * Structures and unions

    * Structure/union alignment and byte order

    * Bit fields in structures and unions

    * Arrays

    * Pointers

    * Type conversions

    * Incomplete Types

    * Callback functions

    * Accessing values exported from dlls

    * Surprises

    * Variable-sized data types

  * ctypes reference

    * Finding shared libraries

    * Loading shared libraries

    * Foreign functions

    * Function prototypes

    * Utility functions

    * Data types

    * Fundamental data types

    * Structured data types

    * Arrays and pointers
