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python-3.7.4-docs-html/_sources/library/sysconfig.rst.txt

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+:mod:`sysconfig` --- Provide access to Python's configuration information
+=========================================================================
+
+.. module:: sysconfig
+   :synopsis: Python's configuration information
+
+.. moduleauthor:: Tarek Ziadé <tarek@ziade.org>
+.. sectionauthor:: Tarek Ziadé <tarek@ziade.org>
+
+.. versionadded:: 3.2
+
+**Source code:** :source:`Lib/sysconfig.py`
+
+.. index::
+   single: configuration information
+
+--------------
+
+The :mod:`sysconfig` module provides access to Python's configuration
+information like the list of installation paths and the configuration variables
+relevant for the current platform.
+
+Configuration variables
+-----------------------
+
+A Python distribution contains a :file:`Makefile` and a :file:`pyconfig.h`
+header file that are necessary to build both the Python binary itself and
+third-party C extensions compiled using :mod:`distutils`.
+
+:mod:`sysconfig` puts all variables found in these files in a dictionary that
+can be accessed using :func:`get_config_vars` or :func:`get_config_var`.
+
+Notice that on Windows, it's a much smaller set.
+
+.. function:: get_config_vars(\*args)
+
+   With no arguments, return a dictionary of all configuration variables
+   relevant for the current platform.
+
+   With arguments, return a list of values that result from looking up each
+   argument in the configuration variable dictionary.
+
+   For each argument, if the value is not found, return ``None``.
+
+
+.. function:: get_config_var(name)
+
+   Return the value of a single variable *name*. Equivalent to
+   ``get_config_vars().get(name)``.
+
+   If *name* is not found, return ``None``.
+
+Example of usage::
+
+   >>> import sysconfig
+   >>> sysconfig.get_config_var('Py_ENABLE_SHARED')
+   0
+   >>> sysconfig.get_config_var('LIBDIR')
+   '/usr/local/lib'
+   >>> sysconfig.get_config_vars('AR', 'CXX')
+   ['ar', 'g++']
+
+
+Installation paths
+------------------
+
+Python uses an installation scheme that differs depending on the platform and on
+the installation options.  These schemes are stored in :mod:`sysconfig` under
+unique identifiers based on the value returned by :const:`os.name`.
+
+Every new component that is installed using :mod:`distutils` or a
+Distutils-based system will follow the same scheme to copy its file in the right
+places.
+
+Python currently supports seven schemes:
+
+- *posix_prefix*: scheme for Posix platforms like Linux or Mac OS X.  This is
+  the default scheme used when Python or a component is installed.
+- *posix_home*: scheme for Posix platforms used when a *home* option is used
+  upon installation.  This scheme is used when a component is installed through
+  Distutils with a specific home prefix.
+- *posix_user*: scheme for Posix platforms used when a component is installed
+  through Distutils and the *user* option is used.  This scheme defines paths
+  located under the user home directory.
+- *nt*: scheme for NT platforms like Windows.
+- *nt_user*: scheme for NT platforms, when the *user* option is used.
+
+Each scheme is itself composed of a series of paths and each path has a unique
+identifier.  Python currently uses eight paths:
+
+- *stdlib*: directory containing the standard Python library files that are not
+  platform-specific.
+- *platstdlib*: directory containing the standard Python library files that are
+  platform-specific.
+- *platlib*: directory for site-specific, platform-specific files.
+- *purelib*: directory for site-specific, non-platform-specific files.
+- *include*: directory for non-platform-specific header files.
+- *platinclude*: directory for platform-specific header files.
+- *scripts*: directory for script files.
+- *data*: directory for data files.
+
+:mod:`sysconfig` provides some functions to determine these paths.
+
+.. function:: get_scheme_names()
+
+   Return a tuple containing all schemes currently supported in
+   :mod:`sysconfig`.
+
+
+.. function:: get_path_names()
+
+   Return a tuple containing all path names currently supported in
+   :mod:`sysconfig`.
+
+
+.. function:: get_path(name, [scheme, [vars, [expand]]])
+
+   Return an installation path corresponding to the path *name*, from the
+   install scheme named *scheme*.
+
+   *name* has to be a value from the list returned by :func:`get_path_names`.
+
+   :mod:`sysconfig` stores installation paths corresponding to each path name,
+   for each platform, with variables to be expanded.  For instance the *stdlib*
+   path for the *nt* scheme is: ``{base}/Lib``.
+
+   :func:`get_path` will use the variables returned by :func:`get_config_vars`
+   to expand the path.  All variables have default values for each platform so
+   one may call this function and get the default value.
+
+   If *scheme* is provided, it must be a value from the list returned by
+   :func:`get_scheme_names`.  Otherwise, the default scheme for the current
+   platform is used.
+
+   If *vars* is provided, it must be a dictionary of variables that will update
+   the dictionary return by :func:`get_config_vars`.
+
+   If *expand* is set to ``False``, the path will not be expanded using the
+   variables.
+
+   If *name* is not found, return ``None``.
+
+
+.. function:: get_paths([scheme, [vars, [expand]]])
+
+   Return a dictionary containing all installation paths corresponding to an
+   installation scheme. See :func:`get_path` for more information.
+
+   If *scheme* is not provided, will use the default scheme for the current
+   platform.
+
+   If *vars* is provided, it must be a dictionary of variables that will
+   update the dictionary used to expand the paths.
+
+   If *expand* is set to false, the paths will not be expanded.
+
+   If *scheme* is not an existing scheme, :func:`get_paths` will raise a
+   :exc:`KeyError`.
+
+
+Other functions
+---------------
+
+.. function:: get_python_version()
+
+   Return the ``MAJOR.MINOR`` Python version number as a string.  Similar to
+   ``'%d.%d' % sys.version_info[:2]``.
+
+
+.. 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
+
+   Windows will return one of:
+
+   - win-amd64 (64bit Windows on AMD64, aka x86_64, Intel64, and EM64T)
+   - win32 (all others - specifically, sys.platform is returned)
+
+   Mac OS X can return:
+
+   - macosx-10.6-ppc
+   - macosx-10.4-ppc64
+   - macosx-10.3-i386
+   - macosx-10.4-fat
+
+   For other non-POSIX platforms, currently just returns :data:`sys.platform`.
+
+
+.. function:: is_python_build()
+
+   Return ``True`` if the running Python interpreter was built from source and
+   is being run from its built location, and not from a location resulting from
+   e.g. running ``make install`` or installing via a binary installer.
+
+
+.. function:: parse_config_h(fp[, vars])
+
+   Parse a :file:`config.h`\-style file.
+
+   *fp* is a file-like object pointing to the :file:`config.h`\-like file.
+
+   A dictionary containing name/value pairs is returned.  If an optional
+   dictionary is passed in as the second argument, it is used instead of a new
+   dictionary, and updated with the values read in the file.
+
+
+.. function:: get_config_h_filename()
+
+   Return the path of :file:`pyconfig.h`.
+
+.. function:: get_makefile_filename()
+
+   Return the path of :file:`Makefile`.
+
+Using :mod:`sysconfig` as a script
+----------------------------------
+
+You can use :mod:`sysconfig` as a script with Python's *-m* option:
+
+.. code-block:: shell-session
+
+    $ python -m sysconfig
+    Platform: "macosx-10.4-i386"
+    Python version: "3.2"
+    Current installation scheme: "posix_prefix"
+
+    Paths:
+            data = "/usr/local"
+            include = "/Users/tarek/Dev/svn.python.org/py3k/Include"
+            platinclude = "."
+            platlib = "/usr/local/lib/python3.2/site-packages"
+            platstdlib = "/usr/local/lib/python3.2"
+            purelib = "/usr/local/lib/python3.2/site-packages"
+            scripts = "/usr/local/bin"
+            stdlib = "/usr/local/lib/python3.2"
+
+    Variables:
+            AC_APPLE_UNIVERSAL_BUILD = "0"
+            AIX_GENUINE_CPLUSPLUS = "0"
+            AR = "ar"
+            ARFLAGS = "rc"
+            ...
+
+This call will print in the standard output the information returned by
+:func:`get_platform`, :func:`get_python_version`, :func:`get_path` and
+:func:`get_config_vars`.