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diff --git a/Doc/library/sysconfig.rst b/Doc/library/sysconfig.rst new file mode 100644 index 0000000..1e89bd0 --- /dev/null +++ b/Doc/library/sysconfig.rst @@ -0,0 +1,259 @@ +:mod:`sysconfig` --- Provide access to Python's configuration information +========================================================================= + +.. module:: sysconfig + :synopsis: Python's configuration information +.. moduleauthor:: Tarek Ziade <tarek@ziade.org> +.. sectionauthor:: Tarek Ziade <tarek@ziade.org> +.. index:: + single: configuration information + +**Source code:** :source:`Lib/sysconfig.py` + +.. versionadded:: 3.2 + +-------------- + +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. +- *os2*: scheme for OS/2 platforms. +- *os2_home*: scheme for OS/2 patforms, 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_path_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 + ``sys.version[:3]``. + + +.. 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 :func:`os.uname`), although the + exact information included depends on the OS; e.g. for IRIX the architecture + isn't particularly important (IRIX only runs on SGI hardware), but for Linux + the kernel version isn't particularly important. + + Examples of returned values: + + - linux-i586 + - linux-alpha (?) + - solaris-2.6-sun4u + - irix-5.3 + - irix64-6.2 + + Windows will return one of: + + - win-amd64 (64bit Windows on AMD64 (aka x86_64, Intel64, EM64T, etc) + - win-ia64 (64bit Windows on Itanium) + - 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 current Python installation was built from source. + + +.. 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:: + + $ 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" + ASDLGEN = "./Parser/asdl_c.py" + ... + +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`. |