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Doc/distutils/apiref.rst
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.. _api-reference:

*************
API Reference
*************

.. seealso::

   `New and changed setup.py arguments in setuptools`_
      The ``setuptools`` project adds new capabilities to the ``setup`` function
      and other APIs, makes the API consistent across different Python versions,
      and is hence recommended over using ``distutils`` directly.

.. _New and changed setup.py arguments in setuptools: https://setuptools.readthedocs.io/en/latest/setuptools.html#new-and-changed-setup-keywords

.. include:: ./_setuptools_disclaimer.rst

:mod:`distutils.core` --- Core Distutils functionality
======================================================

.. module:: distutils.core
   :synopsis: The core Distutils functionality


The :mod:`distutils.core` module is the only module that needs to be installed
to use the Distutils. It provides the :func:`setup` (which is called from the
setup script). Indirectly provides the  :class:`distutils.dist.Distribution` and
:class:`distutils.cmd.Command` class.


.. function:: setup(arguments)

   The basic do-everything function that does most everything you could ever ask
   for from a Distutils method.

   The setup function takes a large number of arguments. These are laid out in the
   following table.

   .. tabularcolumns:: |l|L|L|

   +--------------------+--------------------------------+-------------------------------------------------------------+
   | argument name      | value                          | type                                                        |
   +====================+================================+=============================================================+
   | *name*             | The name of the package        | a string                                                    |
   +--------------------+--------------------------------+-------------------------------------------------------------+
   | *version*          | The version number of the      | a string                                                    |
   |                    | package; see                   |                                                             |
   |                    | :mod:`distutils.version`       |                                                             |
   +--------------------+--------------------------------+-------------------------------------------------------------+
   | *description*      | A single line describing the   | a string                                                    |
   |                    | package                        |                                                             |
   +--------------------+--------------------------------+-------------------------------------------------------------+
   | *long_description* | Longer description of the      | a string                                                    |
   |                    | package                        |                                                             |
   +--------------------+--------------------------------+-------------------------------------------------------------+
   | *author*           | The name of the package author | a string                                                    |
   +--------------------+--------------------------------+-------------------------------------------------------------+
   | *author_email*     | The email address of the       | a string                                                    |
   |                    | package author                 |                                                             |
   +--------------------+--------------------------------+-------------------------------------------------------------+
   | *maintainer*       | The name of the current        | a string                                                    |
   |                    | maintainer, if different from  |                                                             |
   |                    | the author. Note that if       |                                                             |
   |                    | the maintainer is provided,    |                                                             |
   |                    | distutils will use it as the   |                                                             |
   |                    | author in :file:`PKG-INFO`     |                                                             |
   +--------------------+--------------------------------+-------------------------------------------------------------+
   | *maintainer_email* | The email address of the       | a string                                                    |
   |                    | current maintainer, if         |                                                             |
   |                    | different from the author      |                                                             |
   +--------------------+--------------------------------+-------------------------------------------------------------+
   | *url*              | A URL for the package          | a string                                                    |
   |                    | (homepage)                     |                                                             |
   +--------------------+--------------------------------+-------------------------------------------------------------+
   | *download_url*     | A URL to download the package  | a string                                                    |
   +--------------------+--------------------------------+-------------------------------------------------------------+
   | *packages*         | A list of Python packages that | a list of strings                                           |
   |                    | distutils will manipulate      |                                                             |
   +--------------------+--------------------------------+-------------------------------------------------------------+
   | *py_modules*       | A list of Python modules that  | a list of strings                                           |
   |                    | distutils will manipulate      |                                                             |
   +--------------------+--------------------------------+-------------------------------------------------------------+
   | *scripts*          | A list of standalone script    | a list of strings                                           |
   |                    | files to be built and          |                                                             |
   |                    | installed                      |                                                             |
   +--------------------+--------------------------------+-------------------------------------------------------------+
   | *ext_modules*      | A list of Python extensions to | a list of instances of                                      |
   |                    | be built                       | :class:`distutils.core.Extension`                           |
   +--------------------+--------------------------------+-------------------------------------------------------------+
   | *classifiers*      | A list of categories for the   | a list of strings; valid classifiers are listed on `PyPI    |
   |                    | package                        | <https://pypi.org/classifiers>`_.                           |
   +--------------------+--------------------------------+-------------------------------------------------------------+
   | *distclass*        | the :class:`Distribution`      | a subclass of                                               |
   |                    | class to use                   | :class:`distutils.core.Distribution`                        |
   +--------------------+--------------------------------+-------------------------------------------------------------+
   | *script_name*      | The name of the setup.py       | a string                                                    |
   |                    | script - defaults to           |                                                             |
   |                    | ``sys.argv[0]``                |                                                             |
   +--------------------+--------------------------------+-------------------------------------------------------------+
   | *script_args*      | Arguments to supply to the     | a list of strings                                           |
   |                    | setup script                   |                                                             |
   +--------------------+--------------------------------+-------------------------------------------------------------+
   | *options*          | default options for the setup  | a dictionary                                                |
   |                    | script                         |                                                             |
   +--------------------+--------------------------------+-------------------------------------------------------------+
   | *license*          | The license for the package    | a string                                                    |
   +--------------------+--------------------------------+-------------------------------------------------------------+
   | *keywords*         | Descriptive meta-data, see     | a list of strings or a comma-separated string               |
   |                    | :pep:`314`                     |                                                             |
   +--------------------+--------------------------------+-------------------------------------------------------------+
   | *platforms*        |                                | a list of strings or a comma-separated string               |
   +--------------------+--------------------------------+-------------------------------------------------------------+
   | *cmdclass*         | A mapping of command names to  | a dictionary                                                |
   |                    | :class:`Command` subclasses    |                                                             |
   +--------------------+--------------------------------+-------------------------------------------------------------+
   | *data_files*       | A list of data files to        | a list                                                      |
   |                    | install                        |                                                             |
   +--------------------+--------------------------------+-------------------------------------------------------------+
   | *package_dir*      | A mapping of package to        | a dictionary                                                |
   |                    | directory names                |                                                             |
   +--------------------+--------------------------------+-------------------------------------------------------------+



.. function:: run_setup(script_name[, script_args=None, stop_after='run'])

   Run a setup script in a somewhat controlled environment, and return  the
   :class:`distutils.dist.Distribution` instance that drives things.   This is
   useful if you need to find out the distribution meta-data  (passed as keyword
   args from *script* to :func:`setup`), or  the contents of the config files or
   command-line.

   *script_name* is a file that will be read and run with :func:`exec`.  ``sys.argv[0]``
   will be replaced with *script* for the duration of the call.  *script_args* is a
   list of strings; if supplied, ``sys.argv[1:]`` will be replaced by *script_args*
   for the duration  of the call.

   *stop_after* tells :func:`setup` when to stop processing; possible  values:

   .. tabularcolumns:: |l|L|

   +---------------+---------------------------------------------+
   | value         | description                                 |
   +===============+=============================================+
   | *init*        | Stop after the :class:`Distribution`        |
   |               | instance has been created  and populated    |
   |               | with the keyword arguments to :func:`setup` |
   +---------------+---------------------------------------------+
   | *config*      | Stop after config files have been parsed    |
   |               | (and their data stored in the               |
   |               | :class:`Distribution` instance)             |
   +---------------+---------------------------------------------+
   | *commandline* | Stop after the command-line                 |
   |               | (``sys.argv[1:]`` or  *script_args*) have   |
   |               | been parsed (and the data stored in the     |
   |               | :class:`Distribution` instance.)            |
   +---------------+---------------------------------------------+
   | *run*         | Stop after all commands have been run (the  |
   |               | same as  if :func:`setup` had been called   |
   |               | in the usual way). This is the default      |
   |               | value.                                      |
   +---------------+---------------------------------------------+

In addition, the :mod:`distutils.core` module exposed a number of  classes that
live elsewhere.

* :class:`~distutils.extension.Extension` from :mod:`distutils.extension`

* :class:`~distutils.cmd.Command` from :mod:`distutils.cmd`

* :class:`~distutils.dist.Distribution` from :mod:`distutils.dist`

A short description of each of these follows, but see the relevant module for
the full reference.


.. class:: Extension

   The Extension class describes a single C or C++ extension module in a setup
   script. It accepts the following keyword arguments in its constructor:

   .. tabularcolumns:: |l|L|l|

   +------------------------+--------------------------------+---------------------------+
   | argument name          | value                          | type                      |
   +========================+================================+===========================+
   | *name*                 | the full name of the           | a string                  |
   |                        | extension, including any       |                           |
   |                        | packages --- ie. *not* a       |                           |
   |                        | filename or pathname, but      |                           |
   |                        | Python dotted name             |                           |
   +------------------------+--------------------------------+---------------------------+
   | *sources*              | list of source filenames,      | a list of strings         |
   |                        | relative to the distribution   |                           |
   |                        | root (where the setup script   |                           |
   |                        | lives), in Unix form           |                           |
   |                        | (slash-separated) for          |                           |
   |                        | portability.                   |                           |
   |                        | Source files may be C, C++,    |                           |
   |                        | SWIG (.i), platform-specific   |                           |
   |                        | resource files, or whatever    |                           |
   |                        | else is recognized by the      |                           |
   |                        | :command:`build_ext` command   |                           |
   |                        | as source for a Python         |                           |
   |                        | extension.                     |                           |
   +------------------------+--------------------------------+---------------------------+
   | *include_dirs*         | list of directories to search  | a list of strings         |
   |                        | for C/C++ header files (in     |                           |
   |                        | Unix form for portability)     |                           |
   +------------------------+--------------------------------+---------------------------+
   | *define_macros*        | list of macros to define; each | a list of tuples          |
   |                        | macro is defined using a       |                           |
   |                        | 2-tuple ``(name, value)``,     |                           |
   |                        | where *value* is               |                           |
   |                        | either the string to define it |                           |
   |                        | to or ``None`` to define it    |                           |
   |                        | without a particular value     |                           |
   |                        | (equivalent of ``#define FOO`` |                           |
   |                        | in source or :option:`!-DFOO`  |                           |
   |                        | on Unix C compiler command     |                           |
   |                        | line)                          |                           |
   +------------------------+--------------------------------+---------------------------+
   | *undef_macros*         | list of macros to undefine     | a list of strings         |
   |                        | explicitly                     |                           |
   +------------------------+--------------------------------+---------------------------+
   | *library_dirs*         | list of directories to search  | a list of strings         |
   |                        | for C/C++ libraries at link    |                           |
   |                        | time                           |                           |
   +------------------------+--------------------------------+---------------------------+
   | *libraries*            | list of library names (not     | a list of strings         |
   |                        | filenames or paths) to link    |                           |
   |                        | against                        |                           |
   +------------------------+--------------------------------+---------------------------+
   | *runtime_library_dirs* | list of directories to search  | a list of strings         |
   |                        | for C/C++ libraries at run     |                           |
   |                        | time (for shared extensions,   |                           |
   |                        | this is when the extension is  |                           |
   |                        | loaded)                        |                           |
   +------------------------+--------------------------------+---------------------------+
   | *extra_objects*        | list of extra files to link    | a list of strings         |
   |                        | with (eg. object files not     |                           |
   |                        | implied by 'sources', static   |                           |
   |                        | library that must be           |                           |
   |                        | explicitly specified, binary   |                           |
   |                        | resource files, etc.)          |                           |
   +------------------------+--------------------------------+---------------------------+
   | *extra_compile_args*   | any extra platform- and        | a list of strings         |
   |                        | compiler-specific information  |                           |
   |                        | to use when compiling the      |                           |
   |                        | source files in 'sources'. For |                           |
   |                        | platforms and compilers where  |                           |
   |                        | a command line makes sense,    |                           |
   |                        | this is typically a list of    |                           |
   |                        | command-line arguments, but    |                           |
   |                        | for other platforms it could   |                           |
   |                        | be anything.                   |                           |
   +------------------------+--------------------------------+---------------------------+
   | *extra_link_args*      | any extra platform- and        | a list of strings         |
   |                        | compiler-specific information  |                           |
   |                        | to use when linking object     |                           |
   |                        | files together to create the   |                           |
   |                        | extension (or to create a new  |                           |
   |                        | static Python interpreter).    |                           |
   |                        | Similar interpretation as for  |                           |
   |                        | 'extra_compile_args'.          |                           |
   +------------------------+--------------------------------+---------------------------+
   | *export_symbols*       | list of symbols to be exported | a list of strings         |
   |                        | from a shared extension. Not   |                           |
   |                        | used on all platforms, and not |                           |
   |                        | generally necessary for Python |                           |
   |                        | extensions, which typically    |                           |
   |                        | export exactly one symbol:     |                           |
   |                        | ``init`` + extension_name.     |                           |
   +------------------------+--------------------------------+---------------------------+
   | *depends*              | list of files that the         | a list of strings         |
   |                        | extension depends on           |                           |
   +------------------------+--------------------------------+---------------------------+
   | *language*             | extension language (i.e.       | a string                  |
   |                        | ``'c'``, ``'c++'``,            |                           |
   |                        | ``'objc'``). Will be detected  |                           |
   |                        | from the source extensions if  |                           |
   |                        | not provided.                  |                           |
   +------------------------+--------------------------------+---------------------------+
   | *optional*             | specifies that a build failure | a boolean                 |
   |                        | in the extension should not    |                           |
   |                        | abort the build process, but   |                           |
   |                        | simply skip the extension.     |                           |
   +------------------------+--------------------------------+---------------------------+

   .. versionchanged:: 3.8

      On Unix, C extensions are no longer linked to libpython except on
      Android and Cygwin.


.. class:: Distribution

   A :class:`Distribution` describes how to build, install and package up a Python
   software package.

   See the :func:`setup` function for a list of keyword arguments accepted  by the
   Distribution constructor. :func:`setup` creates a Distribution instance.

   .. versionchanged:: 3.7
      :class:`~distutils.core.Distribution` now warns if ``classifiers``,
      ``keywords`` and ``platforms`` fields are not specified as a list or
      a string.

.. class:: Command

   A :class:`Command` class (or rather, an instance of one of its subclasses)
   implement a single distutils command.


:mod:`distutils.ccompiler` --- CCompiler base class
===================================================

.. module:: distutils.ccompiler
   :synopsis: Abstract CCompiler class


This module provides the abstract base class for the :class:`CCompiler`
classes.  A :class:`CCompiler` instance can be used for all the compile  and
link steps needed to build a single project. Methods are provided to  set
options for the compiler --- macro definitions, include directories,  link path,
libraries and the like.

This module provides the following functions.


.. function:: gen_lib_options(compiler, library_dirs, runtime_library_dirs, libraries)

   Generate linker options for searching library directories and linking with
   specific libraries.  *libraries* and *library_dirs* are, respectively, lists of
   library names (not filenames!) and search directories.  Returns a list of
   command-line options suitable for use with some compiler (depending on the two
   format strings passed in).


.. function:: gen_preprocess_options(macros, include_dirs)

   Generate C pre-processor options (:option:`!-D`, :option:`!-U`, :option:`!-I`) as
   used by at least two types of compilers: the typical Unix compiler and Visual
   C++. *macros* is the usual thing, a list of 1- or 2-tuples, where ``(name,)``
   means undefine (:option:`!-U`) macro *name*, and ``(name, value)`` means define
   (:option:`!-D`) macro *name* to *value*.  *include_dirs* is just a list of
   directory names to be added to the header file search path (:option:`!-I`).
   Returns a list of command-line options suitable for either Unix compilers or
   Visual C++.


.. function:: get_default_compiler(osname, platform)

   Determine the default compiler to use for the given platform.

   *osname* should be one of the standard Python OS names (i.e. the ones returned
   by ``os.name``) and *platform* the common value returned by ``sys.platform`` for
   the platform in question.

   The default values are ``os.name`` and ``sys.platform`` in case the parameters
   are not given.


.. function:: new_compiler(plat=None, compiler=None, verbose=0, dry_run=0, force=0)

   Factory function to generate an instance of some CCompiler subclass for the
   supplied platform/compiler combination. *plat* defaults to ``os.name`` (eg.
   ``'posix'``, ``'nt'``), and *compiler*  defaults to the default compiler for
   that platform. Currently only ``'posix'`` and ``'nt'`` are supported, and the
   default compilers are "traditional Unix interface" (:class:`UnixCCompiler`
   class) and Visual C++ (:class:`MSVCCompiler` class).  Note that it's perfectly
   possible to ask for a Unix compiler object under Windows, and a Microsoft
   compiler object under Unix---if you supply a value for *compiler*, *plat* is
   ignored.

   .. % Is the posix/nt only thing still true? macOS seems to work, and
   .. % returns a UnixCCompiler instance. How to document this... hmm.


.. function:: show_compilers()

   Print list of available compilers (used by the :option:`!--help-compiler` options
   to :command:`build`, :command:`build_ext`, :command:`build_clib`).


.. class:: CCompiler([verbose=0, dry_run=0, force=0])

   The abstract base class :class:`CCompiler` defines the interface that  must be
   implemented by real compiler classes.  The class also has  some utility methods
   used by several compiler classes.

   The basic idea behind a compiler abstraction class is that each instance can be
   used for all the compile/link steps in building a single project.  Thus,
   attributes common to all of those compile and link steps --- include
   directories, macros to define, libraries to link against, etc. --- are
   attributes of the compiler instance.  To allow for variability in how individual
   files are treated, most of those attributes may be varied on a per-compilation
   or per-link basis.

   The constructor for each subclass creates an instance of the Compiler object.
   Flags are *verbose* (show verbose output), *dry_run* (don't actually execute the
   steps) and *force* (rebuild everything, regardless of dependencies). All of
   these flags default to ``0`` (off). Note that you probably don't want to
   instantiate :class:`CCompiler` or one of its subclasses directly - use the
   :func:`distutils.CCompiler.new_compiler` factory function instead.

   The following methods allow you to manually alter compiler options for  the
   instance of the Compiler class.


   .. method:: CCompiler.add_include_dir(dir)

      Add *dir* to the list of directories that will be searched for header files.
      The compiler is instructed to search directories in the order in which they are
      supplied by successive calls to :meth:`add_include_dir`.


   .. method:: CCompiler.set_include_dirs(dirs)

      Set the list of directories that will be searched to *dirs* (a list of strings).
      Overrides any preceding calls to :meth:`add_include_dir`; subsequent calls to
      :meth:`add_include_dir` add to the list passed to :meth:`set_include_dirs`.
      This does not affect any list of standard include directories that the compiler
      may search by default.


   .. method:: CCompiler.add_library(libname)

      Add *libname* to the list of libraries that will be included in all links driven
      by this compiler object.  Note that *libname* should \*not\* be the name of a
      file containing a library, but the name of the library itself: the actual
      filename will be inferred by the linker, the compiler, or the compiler class
      (depending on the platform).

      The linker will be instructed to link against libraries in the order they were
      supplied to :meth:`add_library` and/or :meth:`set_libraries`.  It is perfectly
      valid to duplicate library names; the linker will be instructed to link against
      libraries as many times as they are mentioned.


   .. method:: CCompiler.set_libraries(libnames)

      Set the list of libraries to be included in all links driven by this compiler
      object to *libnames* (a list of strings).  This does not affect any standard
      system libraries that the linker may include by default.


   .. method:: CCompiler.add_library_dir(dir)

      Add *dir* to the list of directories that will be searched for libraries
      specified to :meth:`add_library` and :meth:`set_libraries`.  The linker will be
      instructed to search for libraries in the order they are supplied to
      :meth:`add_library_dir` and/or :meth:`set_library_dirs`.


   .. method:: CCompiler.set_library_dirs(dirs)

      Set the list of library search directories to *dirs* (a list of strings).  This
      does not affect any standard library search path that the linker may search by
      default.


   .. method:: CCompiler.add_runtime_library_dir(dir)

      Add *dir* to the list of directories that will be searched for shared libraries
      at runtime.


   .. method:: CCompiler.set_runtime_library_dirs(dirs)

      Set the list of directories to search for shared libraries at runtime to *dirs*
      (a list of strings).  This does not affect any standard search path that the
      runtime linker may search by default.


   .. method:: CCompiler.define_macro(name[, value=None])

      Define a preprocessor macro for all compilations driven by this compiler object.
      The optional parameter *value* should be a string; if it is not supplied, then
      the macro will be defined without an explicit value and the exact outcome
      depends on the compiler used.

      .. XXX true? does ANSI say anything about this?


   .. method:: CCompiler.undefine_macro(name)

      Undefine a preprocessor macro for all compilations driven by this compiler
      object.  If the same macro is defined by :meth:`define_macro` and
      undefined by :meth:`undefine_macro` the last call takes precedence
      (including multiple redefinitions or undefinitions).  If the macro is
      redefined/undefined on a per-compilation basis (ie. in the call to
      :meth:`compile`), then that takes precedence.


   .. method:: CCompiler.add_link_object(object)

      Add *object* to the list of object files (or analogues, such as explicitly named
      library files or the output of "resource compilers") to be included in every
      link driven by this compiler object.


   .. method:: CCompiler.set_link_objects(objects)

      Set the list of object files (or analogues) to be included in every link to
      *objects*.  This does not affect any standard object files that the linker may
      include by default (such as system libraries).

   The following methods implement methods for autodetection of compiler  options,
   providing some functionality similar to GNU :program:`autoconf`.


   .. method:: CCompiler.detect_language(sources)

      Detect the language of a given file, or list of files. Uses the  instance
      attributes :attr:`language_map` (a dictionary), and  :attr:`language_order` (a
      list) to do the job.


   .. method:: CCompiler.find_library_file(dirs, lib[, debug=0])

      Search the specified list of directories for a static or shared library file
      *lib* and return the full path to that file.  If *debug* is true, look for a
      debugging version (if that makes sense on the current platform).  Return
      ``None`` if *lib* wasn't found in any of the specified directories.


   .. method:: CCompiler.has_function(funcname [, includes=None, include_dirs=None, libraries=None, library_dirs=None])

      Return a boolean indicating whether *funcname* is supported on the current
      platform.  The optional arguments can be used to augment the compilation
      environment by providing additional include files and paths and libraries and
      paths.


   .. method:: CCompiler.library_dir_option(dir)

      Return the compiler option to add *dir* to the list of directories searched for
      libraries.


   .. method:: CCompiler.library_option(lib)

      Return the compiler option to add *lib* to the list of libraries linked into the
      shared library or executable.


   .. method:: CCompiler.runtime_library_dir_option(dir)

      Return the compiler option to add *dir* to the list of directories searched for
      runtime libraries.


   .. method:: CCompiler.set_executables(**args)

      Define the executables (and options for them) that will be run to perform the
      various stages of compilation.  The exact set of executables that may be
      specified here depends on the compiler class (via the 'executables' class
      attribute), but most will have:

      +--------------+------------------------------------------+
      | attribute    | description                              |
      +==============+==========================================+
      | *compiler*   | the C/C++ compiler                       |
      +--------------+------------------------------------------+
      | *linker_so*  | linker used to create shared objects and |
      |              | libraries                                |
      +--------------+------------------------------------------+
      | *linker_exe* | linker used to create binary executables |
      +--------------+------------------------------------------+
      | *archiver*   | static library creator                   |
      +--------------+------------------------------------------+

      On platforms with a command-line (Unix, DOS/Windows), each of these is a string
      that will be split into executable name and (optional) list of arguments.
      (Splitting the string is done similarly to how Unix shells operate: words are
      delimited by spaces, but quotes and backslashes can override this.  See
      :func:`distutils.util.split_quoted`.)

   The following methods invoke stages in the build process.


   .. method:: CCompiler.compile(sources[, output_dir=None, macros=None, include_dirs=None, debug=0, extra_preargs=None, extra_postargs=None, depends=None])

      Compile one or more source files. Generates object files (e.g.  transforms a
      :file:`.c` file to a :file:`.o` file.)

      *sources* must be a list of filenames, most likely C/C++ files, but in reality
      anything that can be handled by a particular compiler and compiler class (eg.
      :class:`MSVCCompiler` can handle resource files in *sources*).  Return a list of
      object filenames, one per source filename in *sources*.  Depending on the
      implementation, not all source files will necessarily be compiled, but all
      corresponding object filenames will be returned.

      If *output_dir* is given, object files will be put under it, while retaining
      their original path component.  That is, :file:`foo/bar.c` normally compiles to
      :file:`foo/bar.o` (for a Unix implementation); if *output_dir* is *build*, then
      it would compile to :file:`build/foo/bar.o`.

      *macros*, if given, must be a list of macro definitions.  A macro definition is
      either a ``(name, value)`` 2-tuple or a ``(name,)`` 1-tuple. The former defines
      a macro; if the value is ``None``, the macro is defined without an explicit
      value.  The 1-tuple case undefines a macro.  Later
      definitions/redefinitions/undefinitions take precedence.

      *include_dirs*, if given, must be a list of strings, the directories to add to
      the default include file search path for this compilation only.

      *debug* is a boolean; if true, the compiler will be instructed to output debug
      symbols in (or alongside) the object file(s).

      *extra_preargs* and *extra_postargs* are implementation-dependent. On platforms
      that have the notion of a command-line (e.g. Unix, DOS/Windows), they are most
      likely lists of strings: extra command-line arguments to prepend/append to the
      compiler command line.  On other platforms, consult the implementation class
      documentation.  In any event, they are intended as an escape hatch for those
      occasions when the abstract compiler framework doesn't cut the mustard.

      *depends*, if given, is a list of filenames that all targets depend on.  If a
      source file is older than any file in depends, then the source file will be
      recompiled.  This supports dependency tracking, but only at a coarse
      granularity.

      Raises :exc:`CompileError` on failure.


   .. method:: CCompiler.create_static_lib(objects, output_libname[, output_dir=None, debug=0, target_lang=None])

      Link a bunch of stuff together to create a static library file. The "bunch of
      stuff" consists of the list of object files supplied as *objects*, the extra
      object files supplied to :meth:`add_link_object` and/or
      :meth:`set_link_objects`, the libraries supplied to :meth:`add_library` and/or
      :meth:`set_libraries`, and the libraries supplied as *libraries* (if any).

      *output_libname* should be a library name, not a filename; the filename will be
      inferred from the library name.  *output_dir* is the directory where the library
      file will be put.

      .. XXX defaults to what?

      *debug* is a boolean; if true, debugging information will be included in the
      library (note that on most platforms, it is the compile step where this matters:
      the *debug* flag is included here just for consistency).

      *target_lang* is the target language for which the given objects are being
      compiled. This allows specific linkage time treatment of certain languages.

      Raises :exc:`LibError` on failure.


   .. method:: CCompiler.link(target_desc, objects, output_filename[, output_dir=None, libraries=None, library_dirs=None, runtime_library_dirs=None, export_symbols=None, debug=0, extra_preargs=None, extra_postargs=None, build_temp=None, target_lang=None])

      Link a bunch of stuff together to create an executable or shared library file.

      The "bunch of stuff" consists of the list of object files supplied as *objects*.
      *output_filename* should be a filename.  If *output_dir* is supplied,
      *output_filename* is relative to it (i.e. *output_filename* can provide
      directory components if needed).

      *libraries* is a list of libraries to link against.  These are library names,
      not filenames, since they're translated into filenames in a platform-specific
      way (eg. *foo* becomes :file:`libfoo.a` on Unix and :file:`foo.lib` on
      DOS/Windows).  However, they can include a directory component, which means the
      linker will look in that specific directory rather than searching all the normal
      locations.

      *library_dirs*, if supplied, should be a list of directories to search for
      libraries that were specified as bare library names (ie. no directory
      component).  These are on top of the system default and those supplied to
      :meth:`add_library_dir` and/or :meth:`set_library_dirs`.  *runtime_library_dirs*
      is a list of directories that will be embedded into the shared library and used
      to search for other shared libraries that \*it\* depends on at run-time.  (This
      may only be relevant on Unix.)

      *export_symbols* is a list of symbols that the shared library will export.
      (This appears to be relevant only on Windows.)

      *debug* is as for :meth:`compile` and :meth:`create_static_lib`,  with the
      slight distinction that it actually matters on most platforms (as opposed to
      :meth:`create_static_lib`, which includes a *debug* flag mostly for form's
      sake).

      *extra_preargs* and *extra_postargs* are as for :meth:`compile`  (except of
      course that they supply command-line arguments for the particular linker being
      used).

      *target_lang* is the target language for which the given objects are being
      compiled. This allows specific linkage time treatment of certain languages.

      Raises :exc:`LinkError` on failure.


   .. method:: CCompiler.link_executable(objects, output_progname[, output_dir=None, libraries=None, library_dirs=None, runtime_library_dirs=None, debug=0, extra_preargs=None, extra_postargs=None, target_lang=None])

      Link an executable.  *output_progname* is the name of the file executable, while
      *objects* are a list of object filenames to link in. Other arguments  are as for
      the :meth:`link` method.


   .. method:: CCompiler.link_shared_lib(objects, output_libname[, output_dir=None, libraries=None, library_dirs=None, runtime_library_dirs=None, export_symbols=None, debug=0, extra_preargs=None, extra_postargs=None, build_temp=None, target_lang=None])

      Link a shared library. *output_libname* is the name of the output  library,
      while *objects* is a list of object filenames to link in.  Other arguments are
      as for the :meth:`link` method.


   .. method:: CCompiler.link_shared_object(objects, output_filename[, output_dir=None, libraries=None, library_dirs=None, runtime_library_dirs=None, export_symbols=None, debug=0, extra_preargs=None, extra_postargs=None, build_temp=None, target_lang=None])

      Link a shared object. *output_filename* is the name of the shared object that
      will be created, while *objects* is a list of object filenames  to link in.
      Other arguments are as for the :meth:`link` method.


   .. method:: CCompiler.preprocess(source[, output_file=None, macros=None, include_dirs=None, extra_preargs=None, extra_postargs=None])

      Preprocess a single C/C++ source file, named in *source*. Output will be written
      to file named *output_file*, or *stdout* if *output_file* not supplied.
      *macros* is a list of macro definitions as for :meth:`compile`, which will
      augment the macros set with :meth:`define_macro` and :meth:`undefine_macro`.
      *include_dirs* is a list of directory names that will be added to the  default
      list, in the same way as :meth:`add_include_dir`.

      Raises :exc:`PreprocessError` on failure.

   The following utility methods are defined by the :class:`CCompiler` class, for
   use by the various concrete subclasses.


   .. method:: CCompiler.executable_filename(basename[, strip_dir=0, output_dir=''])

      Returns the filename of the executable for the given *basename*.  Typically for
      non-Windows platforms this is the same as the basename,  while Windows will get
      a :file:`.exe` added.


   .. method:: CCompiler.library_filename(libname[, lib_type='static', strip_dir=0, output_dir=''])

      Returns the filename for the given library name on the current platform. On Unix
      a library with *lib_type* of ``'static'`` will typically  be of the form
      :file:`liblibname.a`, while a *lib_type* of ``'dynamic'``  will be of the form
      :file:`liblibname.so`.


   .. method:: CCompiler.object_filenames(source_filenames[, strip_dir=0, output_dir=''])

      Returns the name of the object files for the given source files.
      *source_filenames* should be a list of filenames.


   .. method:: CCompiler.shared_object_filename(basename[, strip_dir=0, output_dir=''])

      Returns the name of a shared object file for the given file name *basename*.


   .. method:: CCompiler.execute(func, args[, msg=None, level=1])

      Invokes :func:`distutils.util.execute`. This method invokes a  Python function
      *func* with the given arguments *args*, after  logging and taking into account
      the *dry_run* flag.


   .. method:: CCompiler.spawn(cmd)

      Invokes :func:`distutils.util.spawn`. This invokes an external  process to run
      the given command.


   .. method:: CCompiler.mkpath(name[, mode=511])

      Invokes :func:`distutils.dir_util.mkpath`. This creates a directory  and any
      missing ancestor directories.


   .. method:: CCompiler.move_file(src, dst)

      Invokes :meth:`distutils.file_util.move_file`. Renames *src* to  *dst*.


   .. method:: CCompiler.announce(msg[, level=1])

      Write a message using :func:`distutils.log.debug`.


   .. method:: CCompiler.warn(msg)

      Write a warning message *msg* to standard error.


   .. method:: CCompiler.debug_print(msg)

      If the *debug* flag is set on this :class:`CCompiler` instance, print  *msg* to
      standard output, otherwise do nothing.

.. % \subsection{Compiler-specific modules}
.. %
.. % The following modules implement concrete subclasses of the abstract
.. % \class{CCompiler} class. They should not be instantiated directly, but should
.. % be created using \function{distutils.ccompiler.new_compiler()} factory
.. % function.


:mod:`distutils.unixccompiler` --- Unix C Compiler
==================================================

.. module:: distutils.unixccompiler
   :synopsis: UNIX C Compiler


This module provides the :class:`UnixCCompiler` class, a subclass of
:class:`CCompiler` that handles the typical Unix-style command-line  C compiler:

* macros defined with :option:`!-Dname[=value]`

* macros undefined with :option:`!-Uname`

* include search directories specified with :option:`!-Idir`

* libraries specified with :option:`!-llib`

* library search directories specified with :option:`!-Ldir`

* compile handled by :program:`cc` (or similar) executable with :option:`!-c`
  option: compiles :file:`.c` to :file:`.o`

* link static library handled by :program:`ar` command (possibly with
  :program:`ranlib`)

* link shared library handled by :program:`cc` :option:`!-shared`


:mod:`distutils.msvccompiler` --- Microsoft Compiler
====================================================

.. module:: distutils.msvccompiler
   :synopsis: Microsoft Compiler

.. XXX: This is *waaaaay* out of date!

This module provides :class:`MSVCCompiler`, an implementation of the abstract
:class:`CCompiler` class for Microsoft Visual Studio. Typically, extension
modules need to be compiled with the same compiler that was used to compile
Python. For Python 2.3 and earlier, the compiler was Visual Studio 6. For Python
2.4 and 2.5, the compiler is Visual Studio .NET 2003.

:class:`MSVCCompiler` will normally choose the right compiler, linker etc. on
its own. To override this choice, the environment variables *DISTUTILS_USE_SDK*
and *MSSdk* must be both set. *MSSdk* indicates that the current environment has
been setup by the SDK's ``SetEnv.Cmd`` script, or that the environment variables
had been registered when the SDK was installed; *DISTUTILS_USE_SDK* indicates
that the distutils user has made an explicit choice to override the compiler
selection by :class:`MSVCCompiler`.


:mod:`distutils.bcppcompiler` --- Borland Compiler
==================================================

.. module:: distutils.bcppcompiler


This module provides :class:`BorlandCCompiler`, a subclass of the abstract
:class:`CCompiler` class for the Borland C++ compiler.


:mod:`distutils.cygwincompiler` --- Cygwin Compiler
===================================================

.. module:: distutils.cygwinccompiler


This module provides the :class:`CygwinCCompiler` class, a subclass of
:class:`UnixCCompiler` that handles the Cygwin port of the GNU C compiler to
Windows.  It also contains the Mingw32CCompiler class which handles the mingw32
port of GCC (same as cygwin in no-cygwin mode).


:mod:`distutils.archive_util` ---  Archiving utilities
======================================================

.. module:: distutils.archive_util
   :synopsis: Utility functions for creating archive files (tarballs, zip files, ...)


This module provides a few functions for creating archive files, such as
tarballs or zipfiles.


.. function:: make_archive(base_name, format[, root_dir=None, base_dir=None, verbose=0, dry_run=0])

   Create an archive file (eg. ``zip`` or ``tar``).  *base_name*  is the name of
   the file to create, minus any format-specific extension;  *format* is the
   archive format: one of ``zip``, ``tar``, ``gztar``, ``bztar``, ``xztar``, or
   ``ztar``. *root_dir* is a directory that will be the root directory of the
   archive; ie. we typically ``chdir`` into *root_dir* before  creating the
   archive.  *base_dir* is the directory where we start  archiving from; ie.
   *base_dir* will be the common prefix of all files and directories in the
   archive.  *root_dir* and *base_dir* both default to the current directory.
   Returns the name of the archive file.

   .. versionchanged:: 3.5
      Added support for the ``xztar`` format.


.. function:: make_tarball(base_name, base_dir[, compress='gzip', verbose=0, dry_run=0])

   'Create an (optional compressed) archive as a tar file from all files in and
   under *base_dir*. *compress* must be ``'gzip'`` (the default),
   ``'bzip2'``, ``'xz'``, ``'compress'``, or ``None``.  For the ``'compress'``
   method the compression utility named by :program:`compress` must be on the
   default program search path, so this is probably Unix-specific.  The output
   tar file will be named :file:`base_dir.tar`, possibly plus the appropriate
   compression extension (``.gz``, ``.bz2``, ``.xz`` or ``.Z``).  Return the
   output filename.

   .. versionchanged:: 3.5
      Added support for the ``xz`` compression.


.. function:: make_zipfile(base_name, base_dir[, verbose=0, dry_run=0])

   Create a zip file from all files in and under *base_dir*.  The output zip file
   will be named *base_name* + :file:`.zip`.  Uses either the  :mod:`zipfile` Python
   module (if available) or the InfoZIP :file:`zip`  utility (if installed and
   found on the default search path).  If neither  tool is available, raises
   :exc:`DistutilsExecError`.   Returns the name of the output zip file.


:mod:`distutils.dep_util` --- Dependency checking
=================================================

.. module:: distutils.dep_util
   :synopsis: Utility functions for simple dependency checking


This module provides functions for performing simple, timestamp-based
dependency of files and groups of files; also, functions based entirely  on such
timestamp dependency analysis.


.. function:: newer(source, target)

   Return true if *source* exists and is more recently modified than *target*, or
   if *source* exists and *target* doesn't. Return false if both exist and *target*
   is the same age or newer  than *source*. Raise :exc:`DistutilsFileError` if
   *source* does not exist.


.. function:: newer_pairwise(sources, targets)

   Walk two filename lists in parallel, testing if each source is newer than its
   corresponding target.  Return a pair of lists (*sources*, *targets*) where
   source is newer than target, according to the semantics of :func:`newer`.

   .. % % equivalent to a listcomp...


.. function:: newer_group(sources, target[, missing='error'])

   Return true if *target* is out-of-date with respect to any file listed in
   *sources*.  In other words, if *target* exists and is newer than every file in
   *sources*, return false; otherwise return true. *missing* controls what we do
   when a source file is missing; the default (``'error'``) is to blow up with an
   :exc:`OSError` from  inside :func:`os.stat`; if it is ``'ignore'``, we silently
   drop any missing source files; if it is ``'newer'``, any missing source files
   make us assume that *target* is out-of-date (this is handy in "dry-run" mode:
   it'll make you pretend to carry out commands that wouldn't work because inputs
   are missing, but that doesn't matter because you're not actually going to run
   the commands).


:mod:`distutils.dir_util` --- Directory tree operations
=======================================================

.. module:: distutils.dir_util
   :synopsis: Utility functions for operating on directories and directory trees


This module provides functions for operating on directories and trees of
directories.


.. function:: mkpath(name[, mode=0o777, verbose=0, dry_run=0])

   Create a directory and any missing ancestor directories.  If the directory
   already exists (or if *name* is the empty string, which means the current
   directory, which of course exists), then do nothing.  Raise
   :exc:`DistutilsFileError` if unable to create some directory along the way (eg.
   some sub-path exists, but is a file rather than a directory).  If *verbose* is
   true, print a one-line summary of each mkdir to stdout.  Return the list of
   directories actually created.


.. function:: create_tree(base_dir, files[, mode=0o777, verbose=0, dry_run=0])

   Create all the empty directories under *base_dir* needed to put *files* there.
   *base_dir* is just the name of a directory which doesn't necessarily exist
   yet; *files* is a list of filenames to be interpreted relative to *base_dir*.
   *base_dir* + the directory portion of every file in *files* will be created if
   it doesn't already exist.  *mode*, *verbose* and *dry_run* flags  are as for
   :func:`mkpath`.


.. function:: copy_tree(src, dst[, preserve_mode=1, preserve_times=1, preserve_symlinks=0, update=0, verbose=0, dry_run=0])

   Copy an entire directory tree *src* to a new location *dst*.  Both *src* and
   *dst* must be directory names.  If *src* is not a directory, raise
   :exc:`DistutilsFileError`.  If *dst* does  not exist, it is created with
   :func:`mkpath`.  The end result of the  copy is that every file in *src* is
   copied to *dst*, and  directories under *src* are recursively copied to *dst*.
   Return the list of files that were copied or might have been copied, using their
   output name. The return value is unaffected by *update* or *dry_run*: it is
   simply the list of all files under *src*, with the names changed to be under
   *dst*.

   *preserve_mode* and *preserve_times* are the same as for
   :func:`distutils.file_util.copy_file`; note that they only apply to
   regular files, not to
   directories.  If *preserve_symlinks* is true, symlinks will be copied as
   symlinks (on platforms that support them!); otherwise (the default), the
   destination of the symlink will be copied.  *update* and *verbose* are the same
   as for :func:`copy_file`.

   Files in *src* that begin with :file:`.nfs` are skipped (more information on
   these files is available in answer D2 of the `NFS FAQ page
   <http://nfs.sourceforge.net/#section_d>`_).

   .. versionchanged:: 3.3.1
      NFS files are ignored.

.. function:: remove_tree(directory[, verbose=0, dry_run=0])

   Recursively remove *directory* and all files and directories underneath it. Any
   errors are ignored (apart from being reported to ``sys.stdout`` if *verbose* is
   true).


:mod:`distutils.file_util` --- Single file operations
=====================================================

.. module:: distutils.file_util
   :synopsis: Utility functions for operating on single files


This module contains some utility functions for operating on individual files.


.. function:: copy_file(src, dst[, preserve_mode=1, preserve_times=1, update=0, link=None, verbose=0, dry_run=0])

   Copy file *src* to *dst*. If *dst* is a directory, then *src* is copied there
   with the same name; otherwise, it must be a filename. (If the file exists, it
   will be ruthlessly clobbered.) If *preserve_mode* is true (the default), the
   file's mode (type and permission bits, or whatever is analogous on the
   current platform) is copied. If *preserve_times* is true (the default), the
   last-modified and last-access times are copied as well. If *update* is true,
   *src* will only be copied if *dst* does not exist, or if *dst* does exist but
   is older than *src*.

   *link* allows you to make hard links (using :func:`os.link`) or symbolic links
   (using :func:`os.symlink`) instead of copying: set it to ``'hard'`` or
   ``'sym'``; if it is ``None`` (the default), files are copied. Don't set *link*
   on systems that don't support it: :func:`copy_file` doesn't check if hard or
   symbolic linking is available.  It uses :func:`_copy_file_contents` to copy file
   contents.

   Return a tuple ``(dest_name, copied)``: *dest_name* is the actual  name of the
   output file, and *copied* is true if the file was copied  (or would have been
   copied, if *dry_run* true).

   .. % XXX if the destination file already exists, we clobber it if
   .. % copying, but blow up if linking.  Hmmm.  And I don't know what
   .. % macostools.copyfile() does.  Should definitely be consistent, and
   .. % should probably blow up if destination exists and we would be
   .. % changing it (ie. it's not already a hard/soft link to src OR
   .. % (not update) and (src newer than dst)).


.. function:: move_file(src, dst[, verbose, dry_run])

   Move file *src* to *dst*. If *dst* is a directory, the file will be moved into
   it with the same name; otherwise, *src* is just renamed to *dst*.  Returns the
   new full name of the file.

   .. warning::

      Handles cross-device moves on Unix using :func:`copy_file`.  What about
      other systems?


.. function:: write_file(filename, contents)

   Create a file called *filename* and write *contents* (a sequence of strings
   without line terminators) to it.


:mod:`distutils.util` --- Miscellaneous other utility functions
===============================================================

.. module:: distutils.util
   :synopsis: Miscellaneous other utility functions


This module contains other assorted bits and pieces that don't fit into  any
other utility module.


.. function:: get_platform()

   Return a string that identifies the current platform.  This is used mainly to
   distinguish platform-specific build directories and platform-specific built
   distributions.  Typically includes the OS name and version and the
   architecture (as supplied by 'os.uname()'), although the exact information
   included depends on the OS; e.g., on Linux, the kernel version isn't
   particularly important.

   Examples of returned values:

   * ``linux-i586``
   * ``linux-alpha``
   * ``solaris-2.6-sun4u``

   For non-POSIX platforms, currently just returns ``sys.platform``.

   For macOS systems the OS version reflects the minimal version on which
   binaries will run (that is, the value of ``MACOSX_DEPLOYMENT_TARGET``
   during the build of Python), not the OS version of the current system.

   For universal binary builds on macOS the architecture value reflects
   the universal binary status instead of the architecture of the current
   processor. For 32-bit universal binaries the architecture is ``fat``,
   for 64-bit universal binaries the architecture is ``fat64``, and
   for 4-way universal binaries the architecture is ``universal``. Starting
   from Python 2.7 and Python 3.2 the architecture ``fat3`` is used for
   a 3-way universal build (ppc, i386, x86_64) and ``intel`` is used for
   a universal build with the i386 and x86_64 architectures

   Examples of returned values on macOS:

   * ``macosx-10.3-ppc``

   * ``macosx-10.3-fat``

   * ``macosx-10.5-universal``

   * ``macosx-10.6-intel``

   For AIX, Python 3.9 and later return a string starting with "aix", followed
   by additional fields (separated by ``'-'``) that represent the combined
   values of AIX Version, Release and Technology Level (first field), Build Date
   (second field), and bit-size (third field). Python 3.8 and earlier returned
   only a single additional field with the AIX Version and Release.

   Examples of returned values on AIX:

   * ``aix-5307-0747-32`` # 32-bit build on AIX ``oslevel -s``: 5300-07-00-0000

   * ``aix-7105-1731-64`` # 64-bit build on AIX ``oslevel -s``: 7100-05-01-1731

   * ``aix-7.2``          # Legacy form reported in Python 3.8 and earlier

   .. versionchanged:: 3.9
      The AIX platform string format now also includes the technology level,
      build date, and ABI bit-size.


.. function:: convert_path(pathname)

   Return 'pathname' as a name that will work on the native filesystem, i.e. split
   it on '/' and put it back together again using the current directory separator.
   Needed because filenames in the setup script are always supplied in Unix style,
   and have to be converted to the local convention before we can actually use them
   in the filesystem.  Raises :exc:`ValueError` on non-Unix-ish systems if
   *pathname* either  starts or ends with a slash.


.. function:: change_root(new_root, pathname)

   Return *pathname* with *new_root* prepended.  If *pathname* is relative, this is
   equivalent to ``os.path.join(new_root,pathname)`` Otherwise, it requires making
   *pathname* relative and then joining the two, which is tricky on DOS/Windows.


.. function:: check_environ()

   Ensure that 'os.environ' has all the environment variables we guarantee that
   users can use in config files, command-line options, etc.  Currently this
   includes:

   * :envvar:`HOME` - user's home directory (Unix only)
   * :envvar:`PLAT` - description of the current platform, including hardware and
     OS (see :func:`get_platform`)


.. function:: subst_vars(s, local_vars)

   Perform shell/Perl-style variable substitution on *s*.  Every occurrence of
   ``$`` followed by a name is considered a variable, and variable is substituted
   by the value found in the *local_vars* dictionary, or in ``os.environ`` if it's
   not in *local_vars*. *os.environ* is first checked/augmented to guarantee that
   it contains certain values: see :func:`check_environ`.  Raise :exc:`ValueError`
   for any variables not found in either *local_vars* or ``os.environ``.

   Note that this is not a fully-fledged string interpolation function. A valid
   ``$variable`` can consist only of upper and lower case letters, numbers and an
   underscore. No { } or ( ) style quoting is available.


.. function:: split_quoted(s)

   Split a string up according to Unix shell-like rules for quotes and backslashes.
   In short: words are delimited by spaces, as long as those spaces are not escaped
   by a backslash, or inside a quoted string. Single and double quotes are
   equivalent, and the quote characters can be backslash-escaped.  The backslash is
   stripped from any two-character escape sequence, leaving only the escaped
   character.  The quote characters are stripped from any quoted string.  Returns a
   list of words.

   .. % Should probably be moved into the standard library.


.. function:: execute(func, args[, msg=None, verbose=0, dry_run=0])

   Perform some action that affects the outside world (for instance, writing to the
   filesystem).  Such actions are special because they are disabled by the
   *dry_run* flag.  This method takes  care of all that bureaucracy for you; all
   you have to do is supply the function to call and an argument tuple for it (to
   embody the "external action" being performed), and an optional message to print.


.. function:: strtobool(val)

   Convert a string representation of truth to true (1) or false (0).

   True values are ``y``, ``yes``, ``t``, ``true``, ``on``  and ``1``; false values
   are ``n``, ``no``, ``f``, ``false``,  ``off`` and ``0``.  Raises
   :exc:`ValueError` if *val*  is anything else.


.. function:: byte_compile(py_files[, optimize=0, force=0, prefix=None, base_dir=None, verbose=1, dry_run=0, direct=None])

   Byte-compile a collection of Python source files to :file:`.pyc` files in a
   :file:`__pycache__` subdirectory (see :pep:`3147` and :pep:`488`).
   *py_files* is a list of files to compile; any files that don't end in
   :file:`.py` are silently skipped.  *optimize* must be one of the following:

   * ``0`` - don't optimize
   * ``1`` - normal optimization (like ``python -O``)
   * ``2`` - extra optimization (like ``python -OO``)

   If *force* is true, all files are recompiled regardless of timestamps.

   The source filename encoded in each :term:`bytecode` file defaults to the filenames
   listed in *py_files*; you can modify these with *prefix* and *basedir*.
   *prefix* is a string that will be stripped off of each source filename, and
   *base_dir* is a directory name that will be prepended (after *prefix* is
   stripped).  You can supply either or both (or neither) of *prefix* and
   *base_dir*, as you wish.

   If *dry_run* is true, doesn't actually do anything that would affect the
   filesystem.

   Byte-compilation is either done directly in this interpreter process with the
   standard :mod:`py_compile` module, or indirectly by writing a temporary script
   and executing it.  Normally, you should let :func:`byte_compile` figure out to
   use direct compilation or not (see the source for details).  The *direct* flag
   is used by the script generated in indirect mode; unless you know what you're
   doing, leave it set to ``None``.

   .. versionchanged:: 3.2.3
      Create ``.pyc`` files with an :func:`import magic tag
      <imp.get_tag>` in their name, in a :file:`__pycache__` subdirectory
      instead of files without tag in the current directory.

   .. versionchanged:: 3.5
      Create ``.pyc`` files according to :pep:`488`.


.. function:: rfc822_escape(header)

   Return a version of *header* escaped for inclusion in an :rfc:`822` header, by
   ensuring there are 8 spaces space after each newline. Note that it does no other
   modification of the string.

   .. % this _can_ be replaced

.. % \subsection{Distutils objects}


:mod:`distutils.dist` --- The Distribution class
================================================

.. module:: distutils.dist
   :synopsis: Provides the Distribution class, which represents the module distribution being
              built/installed/distributed


This module provides the :class:`~distutils.core.Distribution` class, which
represents the module distribution being built/installed/distributed.


:mod:`distutils.extension` --- The Extension class
==================================================

.. module:: distutils.extension
   :synopsis: Provides the Extension class, used to describe C/C++ extension modules in setup
              scripts


This module provides the :class:`Extension` class, used to describe C/C++
extension modules in setup scripts.

.. % \subsection{Ungrouped modules}
.. % The following haven't been moved into a more appropriate section yet.


:mod:`distutils.debug` --- Distutils debug mode
===============================================

.. module:: distutils.debug
   :synopsis: Provides the debug flag for distutils


This module provides the DEBUG flag.


:mod:`distutils.errors` --- Distutils exceptions
================================================

.. module:: distutils.errors
   :synopsis: Provides standard distutils exceptions


Provides exceptions used by the Distutils modules.  Note that Distutils modules
may raise standard exceptions; in particular, SystemExit is usually raised for
errors that are obviously the end-user's fault (eg. bad command-line arguments).

This module is safe to use in ``from ... import *`` mode; it only exports
symbols whose names start with ``Distutils`` and end with ``Error``.


:mod:`distutils.fancy_getopt` --- Wrapper around the standard getopt module
===========================================================================

.. module:: distutils.fancy_getopt
   :synopsis: Additional getopt functionality


This module provides a wrapper around the standard :mod:`getopt`  module that
provides the following additional features:

* short and long options are tied together

* options have help strings, so :func:`fancy_getopt` could potentially  create a
  complete usage summary

* options set attributes of a passed-in object

* boolean options can have "negative aliases" --- eg. if :option:`!--quiet` is
  the "negative alias" of :option:`!--verbose`, then :option:`!--quiet` on the
  command line sets *verbose* to false.

.. function:: fancy_getopt(options, negative_opt, object, args)

   Wrapper function. *options* is a list of ``(long_option, short_option,
   help_string)`` 3-tuples as described in the constructor for
   :class:`FancyGetopt`. *negative_opt* should be a dictionary mapping option names
   to option names, both the key and value should be in the *options* list.
   *object* is an object which will be used to store values (see the :meth:`getopt`
   method of the :class:`FancyGetopt` class). *args* is the argument list. Will use
   ``sys.argv[1:]`` if you  pass ``None`` as *args*.


.. function:: wrap_text(text, width)

   Wraps *text* to less than *width* wide.


.. class:: FancyGetopt([option_table=None])

   The option_table is a list of 3-tuples: ``(long_option, short_option,
   help_string)``

   If an option takes an argument, its *long_option* should have ``'='`` appended;
   *short_option* should just be a single character, no ``':'`` in any case.
   *short_option* should be ``None`` if a *long_option*  doesn't have a
   corresponding *short_option*. All option tuples must have long options.

The :class:`FancyGetopt` class provides the following methods:


.. method:: FancyGetopt.getopt([args=None, object=None])

   Parse command-line options in args. Store as attributes on *object*.

   If *args* is ``None`` or not supplied, uses ``sys.argv[1:]``.  If *object* is
   ``None`` or not supplied, creates a new :class:`OptionDummy` instance, stores
   option values there, and returns a tuple ``(args, object)``.  If *object* is
   supplied, it is modified in place and :func:`getopt` just returns *args*; in
   both cases, the returned *args* is a modified copy of the passed-in *args* list,
   which is left untouched.

   .. % and args returned are?


.. method:: FancyGetopt.get_option_order()

   Returns the list of ``(option, value)`` tuples processed by the previous run of
   :meth:`getopt`  Raises :exc:`RuntimeError` if :meth:`getopt` hasn't been called
   yet.


.. method:: FancyGetopt.generate_help([header=None])

   Generate help text (a list of strings, one per suggested line of output) from
   the option table for this :class:`FancyGetopt` object.

   If supplied, prints the supplied *header* at the top of the help.


:mod:`distutils.filelist` --- The FileList class
================================================

.. module:: distutils.filelist
   :synopsis: The FileList class, used for poking about the file system and
              building lists of files.


This module provides the :class:`FileList` class, used for poking about the
filesystem and building lists of files.


:mod:`distutils.log` --- Simple :pep:`282`-style logging
========================================================

.. module:: distutils.log
   :synopsis: A simple logging mechanism, :pep:`282`-style


:mod:`distutils.spawn` --- Spawn a sub-process
==============================================

.. module:: distutils.spawn
   :synopsis: Provides the spawn() function


This module provides the :func:`spawn` function, a front-end to  various
platform-specific functions for launching another program in a  sub-process.
Also provides :func:`find_executable` to search the path for a given executable
name.


:mod:`distutils.sysconfig` --- System configuration information
===============================================================

.. module:: distutils.sysconfig
   :synopsis: Low-level access to configuration information of the Python interpreter.
.. moduleauthor:: Fred L. Drake, Jr. <fdrake@acm.org>
.. moduleauthor:: Greg Ward <gward@python.net>
.. sectionauthor:: Fred L. Drake, Jr. <fdrake@acm.org>


The :mod:`distutils.sysconfig` module provides access to Python's low-level
configuration information.  The specific configuration variables available
depend heavily on the platform and configuration. The specific variables depend
on the build process for the specific version of Python being run; the variables
are those found in the :file:`Makefile` and configuration header that are
installed with Python on Unix systems.  The configuration header is called
:file:`pyconfig.h` for Python versions starting with 2.2, and :file:`config.h`
for earlier versions of Python.

Some additional functions are provided which perform some useful manipulations
for other parts of the :mod:`distutils` package.


.. data:: PREFIX

   The result of ``os.path.normpath(sys.prefix)``.


.. data:: EXEC_PREFIX

   The result of ``os.path.normpath(sys.exec_prefix)``.


.. function:: get_config_var(name)

   Return the value of a single variable.  This is equivalent to
   ``get_config_vars().get(name)``.


.. function:: get_config_vars(...)

   Return a set of variable definitions.  If there are no arguments, this returns a
   dictionary mapping names of configuration variables to values.  If arguments are
   provided, they should be strings, and the return value will be a sequence giving
   the associated values. If a given name does not have a corresponding value,
   ``None`` will be included for that variable.


.. function:: get_config_h_filename()

   Return the full path name of the configuration header.  For Unix, this will be
   the header generated by the :program:`configure` script; for other platforms the
   header will have been supplied directly by the Python source distribution.  The
   file is a platform-specific text file.


.. function:: get_makefile_filename()

   Return the full path name of the :file:`Makefile` used to build Python.  For
   Unix, this will be a file generated by the :program:`configure` script; the
   meaning for other platforms will vary.  The file is a platform-specific text
   file, if it exists. This function is only useful on POSIX platforms.


.. function:: get_python_inc([plat_specific[, prefix]])

   Return the directory for either the general or platform-dependent C include
   files.  If *plat_specific* is true, the platform-dependent include directory is
   returned; if false or omitted, the platform-independent directory is returned.
   If *prefix* is given, it is used as either the prefix instead of
   :const:`PREFIX`, or as the exec-prefix instead of :const:`EXEC_PREFIX` if
   *plat_specific* is true.


.. function:: get_python_lib([plat_specific[, standard_lib[, prefix]]])

   Return the directory for either the general or platform-dependent library
   installation.  If *plat_specific* is true, the platform-dependent include
   directory is returned; if false or omitted, the platform-independent directory
   is returned.  If *prefix* is given, it is used as either the prefix instead of
   :const:`PREFIX`, or as the exec-prefix instead of :const:`EXEC_PREFIX` if
   *plat_specific* is true.  If *standard_lib* is true, the directory for the
   standard library is returned rather than the directory for the installation of
   third-party extensions.

The following function is only intended for use within the :mod:`distutils`
package.


.. function:: customize_compiler(compiler)

   Do any platform-specific customization of a
   :class:`distutils.ccompiler.CCompiler` instance.

   This function is only needed on Unix at this time, but should be called
   consistently to support forward-compatibility.  It inserts the information that
   varies across Unix flavors and is stored in Python's :file:`Makefile`.  This
   information includes the selected compiler, compiler and linker options, and the
   extension used by the linker for shared objects.

This function is even more special-purpose, and should only be used from
Python's own build procedures.


.. function:: set_python_build()

   Inform the :mod:`distutils.sysconfig` module that it is being used as part of
   the build process for Python.  This changes a lot of relative locations for
   files, allowing them to be located in the build area rather than in an installed
   Python.


:mod:`distutils.text_file` --- The TextFile class
=================================================

.. module:: distutils.text_file
   :synopsis: Provides the TextFile class, a simple interface to text files


This module provides the :class:`TextFile` class, which gives an interface  to
text files that (optionally) takes care of stripping comments, ignoring  blank
lines, and joining lines with backslashes.


.. class:: TextFile([filename=None, file=None, **options])

   This class provides a file-like object that takes care of all  the things you
   commonly want to do when processing a text file  that has some line-by-line
   syntax: strip comments (as long as ``#``  is your comment character), skip blank
   lines, join adjacent lines by escaping the newline (ie. backslash at end of
   line), strip leading and/or trailing whitespace.  All of these are optional and
   independently controllable.

   The class provides a :meth:`warn` method so you can generate  warning messages
   that report physical line number, even if the  logical line in question spans
   multiple physical lines.  Also  provides :meth:`unreadline` for implementing
   line-at-a-time lookahead.

   :class:`TextFile` instances are create with either *filename*, *file*, or both.
   :exc:`RuntimeError` is raised if both are ``None``. *filename* should be a
   string, and *file* a file object (or something that provides :meth:`readline`
   and :meth:`close`  methods).  It is recommended that you supply at least
   *filename*,  so that :class:`TextFile` can include it in warning messages.  If
   *file* is not supplied, :class:`TextFile` creates its own using the
   :func:`open` built-in function.

   The options are all boolean, and affect the values returned by :meth:`readline`

   .. tabularcolumns:: |l|L|l|

   +------------------+--------------------------------+---------+
   | option name      | description                    | default |
   +==================+================================+=========+
   | *strip_comments* | strip from ``'#'`` to          | true    |
   |                  | end-of-line, as well as any    |         |
   |                  | whitespace leading up to the   |         |
   |                  | ``'#'``\ ---unless it is       |         |
   |                  | escaped by a backslash         |         |
   +------------------+--------------------------------+---------+
   | *lstrip_ws*      | strip leading whitespace from  | false   |
   |                  | each line before returning it  |         |
   +------------------+--------------------------------+---------+
   | *rstrip_ws*      | strip trailing whitespace      | true    |
   |                  | (including line terminator!)   |         |
   |                  | from each line before          |         |
   |                  | returning it.                  |         |
   +------------------+--------------------------------+---------+
   | *skip_blanks*    | skip lines that are empty      | true    |
   |                  | \*after\* stripping comments   |         |
   |                  | and whitespace.  (If both      |         |
   |                  | lstrip_ws and rstrip_ws are    |         |
   |                  | false, then some lines may     |         |
   |                  | consist of solely whitespace:  |         |
   |                  | these will \*not\* be skipped, |         |
   |                  | even if *skip_blanks* is       |         |
   |                  | true.)                         |         |
   +------------------+--------------------------------+---------+
   | *join_lines*     | if a backslash is the last     | false   |
   |                  | non-newline character on a     |         |
   |                  | line after stripping comments  |         |
   |                  | and whitespace, join the       |         |
   |                  | following line to it to form   |         |
   |                  | one logical line; if N         |         |
   |                  | consecutive lines end with a   |         |
   |                  | backslash, then N+1 physical   |         |
   |                  | lines will be joined to form   |         |
   |                  | one logical line.              |         |
   +------------------+--------------------------------+---------+
   | *collapse_join*  | strip leading whitespace from  | false   |
   |                  | lines that are joined to their |         |
   |                  | predecessor; only matters if   |         |
   |                  | ``(join_lines and not          |         |
   |                  | lstrip_ws)``                   |         |
   +------------------+--------------------------------+---------+

   Note that since *rstrip_ws* can strip the trailing newline, the semantics of
   :meth:`readline` must differ from those of the built-in file object's
   :meth:`readline` method!  In particular, :meth:`readline`  returns ``None`` for
   end-of-file: an empty string might just be a  blank line (or an all-whitespace
   line), if *rstrip_ws* is true  but *skip_blanks* is not.


   .. method:: TextFile.open(filename)

      Open a new file *filename*.  This overrides any *file* or *filename*
      constructor arguments.


   .. method:: TextFile.close()

      Close the current file and forget everything we know about it (including the
      filename and the current line number).


   .. method:: TextFile.warn(msg[,line=None])

      Print (to stderr) a warning message tied to the current logical line in the
      current file.  If the current logical line in the file spans multiple physical
      lines, the warning refers to the whole range, such as ``"lines 3-5"``.  If
      *line* is supplied,  it overrides the current line number; it may be a list or
      tuple  to indicate a range of physical lines, or an integer for a  single
      physical line.


   .. method:: TextFile.readline()

      Read and return a single logical line from the current file (or from an internal
      buffer if lines have previously been "unread" with :meth:`unreadline`).  If the
      *join_lines* option  is true, this may involve reading multiple physical lines
      concatenated into a single string.  Updates the current line number,  so calling
      :meth:`warn` after :meth:`readline` emits a warning  about the physical line(s)
      just read.  Returns ``None`` on end-of-file,  since the empty string can occur
      if *rstrip_ws* is true but  *strip_blanks* is not.


   .. method:: TextFile.readlines()

      Read and return the list of all logical lines remaining in the current file.
      This updates the current line number to the last line of the file.


   .. method:: TextFile.unreadline(line)

      Push *line* (a string) onto an internal buffer that will be checked by future
      :meth:`readline` calls.  Handy for implementing a parser with line-at-a-time
      lookahead. Note that lines that are "unread" with :meth:`unreadline` are not
      subsequently re-cleansed (whitespace  stripped, or whatever) when read with
      :meth:`readline`. If multiple calls are made to :meth:`unreadline` before a call
      to :meth:`readline`, the lines will be returned most in most recent first order.


:mod:`distutils.version` --- Version number classes
===================================================

.. module:: distutils.version
   :synopsis: Implements classes that represent module version numbers.


.. % todo
.. % \section{Distutils Commands}
.. %
.. % This part of Distutils implements the various Distutils commands, such
.. % as \code{build}, \code{install} \&c. Each command is implemented as a
.. % separate module, with the command name as the name of the module.


:mod:`distutils.cmd` --- Abstract base class for Distutils commands
===================================================================

.. module:: distutils.cmd
   :synopsis: Provides the abstract base class :class:`~distutils.cmd.Command`. This class
              is subclassed by the modules in the distutils.command subpackage.


This module supplies the abstract base class :class:`Command`.


.. class:: Command(dist)

   Abstract base class for defining command classes, the "worker bees" of the
   Distutils.  A useful analogy for command classes is to think of them as
   subroutines with local variables called *options*.  The options are declared
   in :meth:`initialize_options` and defined (given their final values) in
   :meth:`finalize_options`, both of which must be defined by every command
   class.  The distinction between the two is necessary because option values
   might come from the outside world (command line, config file, ...), and any
   options dependent on other options must be computed after these outside
   influences have been processed --- hence :meth:`finalize_options`.  The body
   of the subroutine, where it does all its work based on the values of its
   options, is the :meth:`run` method, which must also be implemented by every
   command class.

   The class constructor takes a single argument *dist*, a
   :class:`~distutils.core.Distribution` instance.


Creating a new Distutils command
================================

This section outlines the steps to create a new Distutils command.

A new command lives in a module in the :mod:`distutils.command` package. There
is a sample template in that directory called :file:`command_template`.  Copy
this file to a new module with the same name as the new command you're
implementing.  This module should implement a class with the same name as the
module (and the command).  So, for instance, to create the command
``peel_banana`` (so that users can run ``setup.py peel_banana``), you'd copy
:file:`command_template` to :file:`distutils/command/peel_banana.py`, then edit
it so that it's implementing the class :class:`peel_banana`, a subclass of
:class:`distutils.cmd.Command`.

Subclasses of :class:`Command` must define the following methods.

.. method:: Command.initialize_options()

   Set default values for all the options that this command supports.  Note that
   these defaults may be overridden by other commands, by the setup script, by
   config files, or by the command-line.  Thus, this is not the place to code
   dependencies between options; generally, :meth:`initialize_options`
   implementations are just a bunch of ``self.foo = None`` assignments.


.. method:: Command.finalize_options()

   Set final values for all the options that this command supports. This is
   always called as late as possible, ie.  after any option assignments from the
   command-line or from other commands have been done.  Thus, this is the place
   to code option dependencies: if *foo* depends on *bar*, then it is safe to
   set *foo* from *bar* as long as *foo* still has the same value it was
   assigned in :meth:`initialize_options`.


.. method:: Command.run()

   A command's raison d'etre: carry out the action it exists to perform, controlled
   by the options initialized in :meth:`initialize_options`, customized by other
   commands, the setup script, the command-line, and config files, and finalized in
   :meth:`finalize_options`.  All terminal output and filesystem interaction should
   be done by :meth:`run`.


.. attribute:: Command.sub_commands

   *sub_commands* formalizes the notion of a "family" of commands,
   e.g. ``install`` as the parent with sub-commands ``install_lib``,
   ``install_headers``, etc.  The parent of a family of commands defines
   *sub_commands* as a class attribute; it's a list of 2-tuples ``(command_name,
   predicate)``, with *command_name* a string and *predicate* a function, a
   string or ``None``.  *predicate* is a method of the parent command that
   determines whether the corresponding command is applicable in the current
   situation.  (E.g. ``install_headers`` is only applicable if we have any C
   header files to install.)  If *predicate* is ``None``, that command is always
   applicable.

   *sub_commands* is usually defined at the *end* of a class, because
   predicates can be methods of the class, so they must already have been
   defined.  The canonical example is the :command:`install` command.


:mod:`distutils.command` --- Individual Distutils commands
==========================================================

.. module:: distutils.command
   :synopsis: Contains one module for each standard Distutils command.


.. % \subsubsection{Individual Distutils commands}
.. % todo


:mod:`distutils.command.bdist` --- Build a binary installer
===========================================================

.. module:: distutils.command.bdist
   :synopsis: Build a binary installer for a package


.. % todo


:mod:`distutils.command.bdist_packager` --- Abstract base class for packagers
=============================================================================

.. module:: distutils.command.bdist_packager
   :synopsis: Abstract base class for packagers


.. % todo


:mod:`distutils.command.bdist_dumb` --- Build a "dumb" installer
================================================================

.. module:: distutils.command.bdist_dumb
   :synopsis: Build a "dumb" installer - a simple archive of files


.. % todo


:mod:`distutils.command.bdist_msi` --- Build a Microsoft Installer binary package
=================================================================================

.. module:: distutils.command.bdist_msi
   :synopsis: Build a binary distribution as a Windows MSI file

.. class:: bdist_msi

.. deprecated:: 3.9
   Use bdist_wheel (wheel packages) instead.

   Builds a `Windows Installer`_ (.msi) binary package.

   .. _Windows Installer: https://msdn.microsoft.com/en-us/library/cc185688(VS.85).aspx

   In most cases, the ``bdist_msi`` installer is a better choice than the
   ``bdist_wininst`` installer, because it provides better support for
   Win64 platforms, allows administrators to perform non-interactive
   installations, and allows installation through group policies.


:mod:`distutils.command.bdist_rpm` --- Build a binary distribution as a Redhat RPM and SRPM
===========================================================================================

.. module:: distutils.command.bdist_rpm
   :synopsis: Build a binary distribution as a Redhat RPM and SRPM


.. % todo


:mod:`distutils.command.bdist_wininst` --- Build a Windows installer
====================================================================

.. module:: distutils.command.bdist_wininst
   :synopsis: Build a Windows installer

.. deprecated:: 3.8
   Use bdist_wheel (wheel packages) instead.


.. % todo


:mod:`distutils.command.sdist` --- Build a source distribution
==============================================================

.. module:: distutils.command.sdist
   :synopsis: Build a source distribution


.. % todo


:mod:`distutils.command.build` --- Build all files of a package
===============================================================

.. module:: distutils.command.build
   :synopsis: Build all files of a package


.. % todo


:mod:`distutils.command.build_clib` --- Build any C libraries in a package
==========================================================================

.. module:: distutils.command.build_clib
   :synopsis: Build any C libraries in a package


.. % todo


:mod:`distutils.command.build_ext` --- Build any extensions in a package
========================================================================

.. module:: distutils.command.build_ext
   :synopsis: Build any extensions in a package


.. % todo


:mod:`distutils.command.build_py` --- Build the .py/.pyc files of a package
===========================================================================

.. module:: distutils.command.build_py
   :synopsis: Build the .py/.pyc files of a package


.. class:: build_py

.. class:: build_py_2to3

   Alternative implementation of build_py which also runs the
   2to3 conversion library on each .py file that is going to be
   installed. To use this in a setup.py file for a distribution
   that is designed to run with both Python 2.x and 3.x, add::

     try:
         from distutils.command.build_py import build_py_2to3 as build_py
     except ImportError:
         from distutils.command.build_py import build_py

   to your setup.py, and later::

      cmdclass = {'build_py': build_py}

   to the invocation of setup().


:mod:`distutils.command.build_scripts` --- Build the scripts of a package
=========================================================================

.. module:: distutils.command.build_scripts
   :synopsis: Build the scripts of a package


.. % todo


:mod:`distutils.command.clean` --- Clean a package build area
=============================================================

.. module:: distutils.command.clean
   :synopsis: Clean a package build area

This command removes the temporary files created by :command:`build`
and its subcommands, like intermediary compiled object files.  With
the ``--all`` option, the complete build directory will be removed.

Extension modules built :ref:`in place <distutils-build-ext-inplace>`
will not be cleaned, as they are not in the build directory.


:mod:`distutils.command.config` --- Perform package configuration
=================================================================

.. module:: distutils.command.config
   :synopsis: Perform package configuration


.. % todo


:mod:`distutils.command.install` --- Install a package
======================================================

.. module:: distutils.command.install
   :synopsis: Install a package


.. % todo


:mod:`distutils.command.install_data` --- Install data files from a package
===========================================================================

.. module:: distutils.command.install_data
   :synopsis: Install data files from a package


.. % todo


:mod:`distutils.command.install_headers` --- Install C/C++ header files from a package
======================================================================================

.. module:: distutils.command.install_headers
   :synopsis: Install C/C++ header files from a package


.. % todo


:mod:`distutils.command.install_lib` --- Install library files from a package
=============================================================================

.. module:: distutils.command.install_lib
   :synopsis: Install library files from a package


.. % todo


:mod:`distutils.command.install_scripts` --- Install script files from a package
================================================================================

.. module:: distutils.command.install_scripts
   :synopsis: Install script files from a package


.. % todo


:mod:`distutils.command.register` --- Register a module with the Python Package Index
=====================================================================================

.. module:: distutils.command.register
   :synopsis: Register a module with the Python Package Index


The ``register`` command registers the package with the Python Package  Index.
This is described in more detail in :pep:`301`.

.. % todo


:mod:`distutils.command.check` --- Check the meta-data of a package
===================================================================

.. module:: distutils.command.check
   :synopsis: Check the meta-data of a package


The ``check`` command performs some tests on the meta-data of a package.
For example, it verifies that all required meta-data are provided as
the arguments passed to the :func:`setup` function.

.. % todo