32.10. "py_compile" — Compile Python source files
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**Source code:** Lib/py_compile.py

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The "py_compile" module provides a function to generate a byte-code
file from a source file, and another function used when the module
source file is invoked as a script.

Though not often needed, this function can be useful when installing
modules for shared use, especially if some of the users may not have
permission to write the byte-code cache files in the directory
containing the source code.

exception py_compile.PyCompileError

   Exception raised when an error occurs while attempting to compile
   the file.

py_compile.compile(file, cfile=None, dfile=None, doraise=False, optimize=-1)

   Compile a source file to byte-code and write out the byte-code
   cache file. The source code is loaded from the file named *file*.
   The byte-code is written to *cfile*, which defaults to the **PEP
   3147**/**PEP 488** path, ending in ".pyc". For example, if *file*
   is "/foo/bar/baz.py" *cfile* will default to
   "/foo/bar/__pycache__/baz.cpython-32.pyc" for Python 3.2.  If
   *dfile* is specified, it is used as the name of the source file in
   error messages when instead of *file*.  If *doraise* is true, a
   "PyCompileError" is raised when an error is encountered while
   compiling *file*. If *doraise* is false (the default), an error
   string is written to "sys.stderr", but no exception is raised.
   This function returns the path to byte-compiled file, i.e. whatever
   *cfile* value was used.

   If the path that *cfile* becomes (either explicitly specified or
   computed) is a symlink or non-regular file, "FileExistsError" will
   be raised. This is to act as a warning that import will turn those
   paths into regular files if it is allowed to write byte-compiled
   files to those paths. This is a side-effect of import using file
   renaming to place the final byte-compiled file into place to
   prevent concurrent file writing issues.

   *optimize* controls the optimization level and is passed to the
   built-in "compile()" function.  The default of "-1" selects the
   optimization level of the current interpreter.

   Changed in version 3.2: Changed default value of *cfile* to be
   **PEP 3147**-compliant.  Previous default was *file* + "'c'" ("'o'"
   if optimization was enabled). Also added the *optimize* parameter.

   Changed in version 3.4: Changed code to use "importlib" for the
   byte-code cache file writing. This means file creation/writing
   semantics now match what "importlib" does, e.g. permissions, write-
   and-move semantics, etc. Also added the caveat that
   "FileExistsError" is raised if *cfile* is a symlink or non-regular
   file.

py_compile.main(args=None)

   Compile several source files.  The files named in *args* (or on the
   command line, if *args* is "None") are compiled and the resulting
   byte-code is cached in the normal manner.  This function does not
   search a directory structure to locate source files; it only
   compiles files named explicitly. If "'-'" is the only parameter in
   args, the list of files is taken from standard input.

   Changed in version 3.2: Added support for "'-'".

When this module is run as a script, the "main()" is used to compile
all the files named on the command line.  The exit status is nonzero
if one of the files could not be compiled.

See also:

  Module "compileall"
     Utilities to compile all Python source files in a directory tree.
