Edit File: sysconfig.html
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>27.2. sysconfig — Provide access to Python’s configuration information — Python 2.7.5 documentation</title> <link rel="stylesheet" href="../_static/default.css" type="text/css" /> <link rel="stylesheet" href="../_static/pygments.css" type="text/css" /> <script type="text/javascript"> var DOCUMENTATION_OPTIONS = { URL_ROOT: '../', VERSION: '2.7.5', COLLAPSE_INDEX: false, FILE_SUFFIX: '.html', HAS_SOURCE: true }; </script> <script type="text/javascript" src="../_static/jquery.js"></script> <script type="text/javascript" src="../_static/underscore.js"></script> <script type="text/javascript" src="../_static/doctools.js"></script> <script type="text/javascript" src="../_static/sidebar.js"></script> <link rel="search" type="application/opensearchdescription+xml" title="Search within Python 2.7.5 documentation" href="../_static/opensearch.xml"/> <link rel="author" title="About these documents" href="../about.html" /> <link rel="copyright" title="Copyright" href="../copyright.html" /> <link rel="top" title="Python 2.7.5 documentation" href="../index.html" /> <link rel="up" title="27. Python Runtime Services" href="python.html" /> <link rel="next" title="27.3. __builtin__ — Built-in objects" href="__builtin__.html" /> <link rel="prev" title="27.1. sys — System-specific parameters and functions" href="sys.html" /> <link rel="shortcut icon" type="image/png" href="../_static/py.png" /> <script type="text/javascript" src="../_static/copybutton.js"></script> </head> <body> <div class="related"> <h3>Navigation</h3> <ul> <li class="right" style="margin-right: 10px"> <a href="../genindex.html" title="General Index" accesskey="I">index</a></li> <li class="right" > <a href="../py-modindex.html" title="Python Module Index" >modules</a> |</li> <li class="right" > <a href="__builtin__.html" title="27.3. __builtin__ — Built-in objects" accesskey="N">next</a> |</li> <li class="right" > <a href="sys.html" title="27.1. sys — System-specific parameters and functions" accesskey="P">previous</a> |</li> <li><img src="../_static/py.png" alt="" style="vertical-align: middle; margin-top: -1px"/></li> <li><a href="http://www.python.org/">Python</a> »</li> <li> <a href="../index.html">Python 2.7.5 documentation</a> » </li> <li><a href="index.html" >The Python Standard Library</a> »</li> <li><a href="python.html" accesskey="U">27. Python Runtime Services</a> »</li> </ul> </div> <div class="document"> <div class="documentwrapper"> <div class="bodywrapper"> <div class="body"> <div class="section" id="module-sysconfig"> <span id="sysconfig-provide-access-to-python-s-configuration-information"></span><h1>27.2. <a class="reference internal" href="#module-sysconfig" title="sysconfig: Python's configuration information"><tt class="xref py py-mod docutils literal"><span class="pre">sysconfig</span></tt></a> — Provide access to Python’s configuration information<a class="headerlink" href="#module-sysconfig" title="Permalink to this headline">¶</a></h1> <p class="versionadded" id="index-0"> <span class="versionmodified">New in version 2.7.</span></p> <p><strong>Source code:</strong> <a class="reference external" href="http://hg.python.org/cpython/file/2.7/Lib/sysconfig.py">Lib/sysconfig.py</a></p> <hr class="docutils" /> <p>The <a class="reference internal" href="#module-sysconfig" title="sysconfig: Python's configuration information"><tt class="xref py py-mod docutils literal"><span class="pre">sysconfig</span></tt></a> module provides access to Python’s configuration information like the list of installation paths and the configuration variables relevant for the current platform.</p> <div class="section" id="configuration-variables"> <h2>27.2.1. Configuration variables<a class="headerlink" href="#configuration-variables" title="Permalink to this headline">¶</a></h2> <p>A Python distribution contains a <tt class="file docutils literal"><span class="pre">Makefile</span></tt> and a <tt class="file docutils literal"><span class="pre">pyconfig.h</span></tt> header file that are necessary to build both the Python binary itself and third-party C extensions compiled using <a class="reference internal" href="distutils.html#module-distutils" title="distutils: Support for building and installing Python modules into an existing Python installation."><tt class="xref py py-mod docutils literal"><span class="pre">distutils</span></tt></a>.</p> <p><a class="reference internal" href="#module-sysconfig" title="sysconfig: Python's configuration information"><tt class="xref py py-mod docutils literal"><span class="pre">sysconfig</span></tt></a> puts all variables found in these files in a dictionary that can be accessed using <a class="reference internal" href="#sysconfig.get_config_vars" title="sysconfig.get_config_vars"><tt class="xref py py-func docutils literal"><span class="pre">get_config_vars()</span></tt></a> or <a class="reference internal" href="#sysconfig.get_config_var" title="sysconfig.get_config_var"><tt class="xref py py-func docutils literal"><span class="pre">get_config_var()</span></tt></a>.</p> <p>Notice that on Windows, it’s a much smaller set.</p> <dl class="function"> <dt id="sysconfig.get_config_vars"> <tt class="descclassname">sysconfig.</tt><tt class="descname">get_config_vars</tt><big>(</big><em>*args</em><big>)</big><a class="headerlink" href="#sysconfig.get_config_vars" title="Permalink to this definition">¶</a></dt> <dd><p>With no arguments, return a dictionary of all configuration variables relevant for the current platform.</p> <p>With arguments, return a list of values that result from looking up each argument in the configuration variable dictionary.</p> <p>For each argument, if the value is not found, return <tt class="docutils literal"><span class="pre">None</span></tt>.</p> </dd></dl> <dl class="function"> <dt id="sysconfig.get_config_var"> <tt class="descclassname">sysconfig.</tt><tt class="descname">get_config_var</tt><big>(</big><em>name</em><big>)</big><a class="headerlink" href="#sysconfig.get_config_var" title="Permalink to this definition">¶</a></dt> <dd><p>Return the value of a single variable <em>name</em>. Equivalent to <tt class="docutils literal"><span class="pre">get_config_vars().get(name)</span></tt>.</p> <p>If <em>name</em> is not found, return <tt class="docutils literal"><span class="pre">None</span></tt>.</p> </dd></dl> <p>Example of usage:</p> <div class="highlight-python"><div class="highlight"><pre><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">sysconfig</span> <span class="gp">>>> </span><span class="n">sysconfig</span><span class="o">.</span><span class="n">get_config_var</span><span class="p">(</span><span class="s">'Py_ENABLE_SHARED'</span><span class="p">)</span> <span class="go">0</span> <span class="gp">>>> </span><span class="n">sysconfig</span><span class="o">.</span><span class="n">get_config_var</span><span class="p">(</span><span class="s">'LIBDIR'</span><span class="p">)</span> <span class="go">'/usr/local/lib'</span> <span class="gp">>>> </span><span class="n">sysconfig</span><span class="o">.</span><span class="n">get_config_vars</span><span class="p">(</span><span class="s">'AR'</span><span class="p">,</span> <span class="s">'CXX'</span><span class="p">)</span> <span class="go">['ar', 'g++']</span> </pre></div> </div> </div> <div class="section" id="installation-paths"> <h2>27.2.2. Installation paths<a class="headerlink" href="#installation-paths" title="Permalink to this headline">¶</a></h2> <p>Python uses an installation scheme that differs depending on the platform and on the installation options. These schemes are stored in <a class="reference internal" href="#module-sysconfig" title="sysconfig: Python's configuration information"><tt class="xref py py-mod docutils literal"><span class="pre">sysconfig</span></tt></a> under unique identifiers based on the value returned by <a class="reference internal" href="os.html#os.name" title="os.name"><tt class="xref py py-const docutils literal"><span class="pre">os.name</span></tt></a>.</p> <p>Every new component that is installed using <a class="reference internal" href="distutils.html#module-distutils" title="distutils: Support for building and installing Python modules into an existing Python installation."><tt class="xref py py-mod docutils literal"><span class="pre">distutils</span></tt></a> or a Distutils-based system will follow the same scheme to copy its file in the right places.</p> <p>Python currently supports seven schemes:</p> <ul class="simple"> <li><em>posix_prefix</em>: scheme for Posix platforms like Linux or Mac OS X. This is the default scheme used when Python or a component is installed.</li> <li><em>posix_home</em>: scheme for Posix platforms used when a <em>home</em> option is used upon installation. This scheme is used when a component is installed through Distutils with a specific home prefix.</li> <li><em>posix_user</em>: scheme for Posix platforms used when a component is installed through Distutils and the <em>user</em> option is used. This scheme defines paths located under the user home directory.</li> <li><em>nt</em>: scheme for NT platforms like Windows.</li> <li><em>nt_user</em>: scheme for NT platforms, when the <em>user</em> option is used.</li> <li><em>os2</em>: scheme for OS/2 platforms.</li> <li><em>os2_home</em>: scheme for OS/2 patforms, when the <em>user</em> option is used.</li> </ul> <p>Each scheme is itself composed of a series of paths and each path has a unique identifier. Python currently uses eight paths:</p> <ul class="simple"> <li><em>stdlib</em>: directory containing the standard Python library files that are not platform-specific.</li> <li><em>platstdlib</em>: directory containing the standard Python library files that are platform-specific.</li> <li><em>platlib</em>: directory for site-specific, platform-specific files.</li> <li><em>purelib</em>: directory for site-specific, non-platform-specific files.</li> <li><em>include</em>: directory for non-platform-specific header files.</li> <li><em>platinclude</em>: directory for platform-specific header files.</li> <li><em>scripts</em>: directory for script files.</li> <li><em>data</em>: directory for data files.</li> </ul> <p><a class="reference internal" href="#module-sysconfig" title="sysconfig: Python's configuration information"><tt class="xref py py-mod docutils literal"><span class="pre">sysconfig</span></tt></a> provides some functions to determine these paths.</p> <dl class="function"> <dt id="sysconfig.get_scheme_names"> <tt class="descclassname">sysconfig.</tt><tt class="descname">get_scheme_names</tt><big>(</big><big>)</big><a class="headerlink" href="#sysconfig.get_scheme_names" title="Permalink to this definition">¶</a></dt> <dd><p>Return a tuple containing all schemes currently supported in <a class="reference internal" href="#module-sysconfig" title="sysconfig: Python's configuration information"><tt class="xref py py-mod docutils literal"><span class="pre">sysconfig</span></tt></a>.</p> </dd></dl> <dl class="function"> <dt id="sysconfig.get_path_names"> <tt class="descclassname">sysconfig.</tt><tt class="descname">get_path_names</tt><big>(</big><big>)</big><a class="headerlink" href="#sysconfig.get_path_names" title="Permalink to this definition">¶</a></dt> <dd><p>Return a tuple containing all path names currently supported in <a class="reference internal" href="#module-sysconfig" title="sysconfig: Python's configuration information"><tt class="xref py py-mod docutils literal"><span class="pre">sysconfig</span></tt></a>.</p> </dd></dl> <dl class="function"> <dt id="sysconfig.get_path"> <tt class="descclassname">sysconfig.</tt><tt class="descname">get_path</tt><big>(</big><em>name</em><span class="optional">[</span>, <em>scheme</em><span class="optional">[</span>, <em>vars</em><span class="optional">[</span>, <em>expand</em><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><big>)</big><a class="headerlink" href="#sysconfig.get_path" title="Permalink to this definition">¶</a></dt> <dd><p>Return an installation path corresponding to the path <em>name</em>, from the install scheme named <em>scheme</em>.</p> <p><em>name</em> has to be a value from the list returned by <a class="reference internal" href="#sysconfig.get_path_names" title="sysconfig.get_path_names"><tt class="xref py py-func docutils literal"><span class="pre">get_path_names()</span></tt></a>.</p> <p><a class="reference internal" href="#module-sysconfig" title="sysconfig: Python's configuration information"><tt class="xref py py-mod docutils literal"><span class="pre">sysconfig</span></tt></a> stores installation paths corresponding to each path name, for each platform, with variables to be expanded. For instance the <em>stdlib</em> path for the <em>nt</em> scheme is: <tt class="docutils literal"><span class="pre">{base}/Lib</span></tt>.</p> <p><a class="reference internal" href="#sysconfig.get_path" title="sysconfig.get_path"><tt class="xref py py-func docutils literal"><span class="pre">get_path()</span></tt></a> will use the variables returned by <a class="reference internal" href="#sysconfig.get_config_vars" title="sysconfig.get_config_vars"><tt class="xref py py-func docutils literal"><span class="pre">get_config_vars()</span></tt></a> to expand the path. All variables have default values for each platform so one may call this function and get the default value.</p> <p>If <em>scheme</em> is provided, it must be a value from the list returned by <a class="reference internal" href="#sysconfig.get_scheme_names" title="sysconfig.get_scheme_names"><tt class="xref py py-func docutils literal"><span class="pre">get_scheme_names()</span></tt></a>. Otherwise, the default scheme for the current platform is used.</p> <p>If <em>vars</em> is provided, it must be a dictionary of variables that will update the dictionary return by <a class="reference internal" href="#sysconfig.get_config_vars" title="sysconfig.get_config_vars"><tt class="xref py py-func docutils literal"><span class="pre">get_config_vars()</span></tt></a>.</p> <p>If <em>expand</em> is set to <tt class="docutils literal"><span class="pre">False</span></tt>, the path will not be expanded using the variables.</p> <p>If <em>name</em> is not found, return <tt class="docutils literal"><span class="pre">None</span></tt>.</p> </dd></dl> <dl class="function"> <dt id="sysconfig.get_paths"> <tt class="descclassname">sysconfig.</tt><tt class="descname">get_paths</tt><big>(</big><span class="optional">[</span><em>scheme</em><span class="optional">[</span>, <em>vars</em><span class="optional">[</span>, <em>expand</em><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><big>)</big><a class="headerlink" href="#sysconfig.get_paths" title="Permalink to this definition">¶</a></dt> <dd><p>Return a dictionary containing all installation paths corresponding to an installation scheme. See <a class="reference internal" href="#sysconfig.get_path" title="sysconfig.get_path"><tt class="xref py py-func docutils literal"><span class="pre">get_path()</span></tt></a> for more information.</p> <p>If <em>scheme</em> is not provided, will use the default scheme for the current platform.</p> <p>If <em>vars</em> is provided, it must be a dictionary of variables that will update the dictionary used to expand the paths.</p> <p>If <em>expand</em> is set to False, the paths will not be expanded.</p> <p>If <em>scheme</em> is not an existing scheme, <a class="reference internal" href="#sysconfig.get_paths" title="sysconfig.get_paths"><tt class="xref py py-func docutils literal"><span class="pre">get_paths()</span></tt></a> will raise a <a class="reference internal" href="exceptions.html#exceptions.KeyError" title="exceptions.KeyError"><tt class="xref py py-exc docutils literal"><span class="pre">KeyError</span></tt></a>.</p> </dd></dl> </div> <div class="section" id="other-functions"> <h2>27.2.3. Other functions<a class="headerlink" href="#other-functions" title="Permalink to this headline">¶</a></h2> <dl class="function"> <dt id="sysconfig.get_python_version"> <tt class="descclassname">sysconfig.</tt><tt class="descname">get_python_version</tt><big>(</big><big>)</big><a class="headerlink" href="#sysconfig.get_python_version" title="Permalink to this definition">¶</a></dt> <dd><p>Return the <tt class="docutils literal"><span class="pre">MAJOR.MINOR</span></tt> Python version number as a string. Similar to <tt class="docutils literal"><span class="pre">sys.version[:3]</span></tt>.</p> </dd></dl> <dl class="function"> <dt id="sysconfig.get_platform"> <tt class="descclassname">sysconfig.</tt><tt class="descname">get_platform</tt><big>(</big><big>)</big><a class="headerlink" href="#sysconfig.get_platform" title="Permalink to this definition">¶</a></dt> <dd><p>Return a string that identifies the current platform.</p> <p>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 <a class="reference internal" href="os.html#os.uname" title="os.uname"><tt class="xref py py-func docutils literal"><span class="pre">os.uname()</span></tt></a>), 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.</p> <p>Examples of returned values:</p> <ul class="simple"> <li>linux-i586</li> <li>linux-alpha (?)</li> <li>solaris-2.6-sun4u</li> <li>irix-5.3</li> <li>irix64-6.2</li> </ul> <p>Windows will return one of:</p> <ul class="simple"> <li>win-amd64 (64bit Windows on AMD64 (aka x86_64, Intel64, EM64T, etc)</li> <li>win-ia64 (64bit Windows on Itanium)</li> <li>win32 (all others - specifically, sys.platform is returned)</li> </ul> <p>Mac OS X can return:</p> <ul class="simple"> <li>macosx-10.6-ppc</li> <li>macosx-10.4-ppc64</li> <li>macosx-10.3-i386</li> <li>macosx-10.4-fat</li> </ul> <p>For other non-POSIX platforms, currently just returns <a class="reference internal" href="sys.html#sys.platform" title="sys.platform"><tt class="xref py py-data docutils literal"><span class="pre">sys.platform</span></tt></a>.</p> </dd></dl> <dl class="function"> <dt id="sysconfig.is_python_build"> <tt class="descclassname">sysconfig.</tt><tt class="descname">is_python_build</tt><big>(</big><big>)</big><a class="headerlink" href="#sysconfig.is_python_build" title="Permalink to this definition">¶</a></dt> <dd><p>Return <tt class="docutils literal"><span class="pre">True</span></tt> if the current Python installation was built from source.</p> </dd></dl> <dl class="function"> <dt id="sysconfig.parse_config_h"> <tt class="descclassname">sysconfig.</tt><tt class="descname">parse_config_h</tt><big>(</big><em>fp</em><span class="optional">[</span>, <em>vars</em><span class="optional">]</span><big>)</big><a class="headerlink" href="#sysconfig.parse_config_h" title="Permalink to this definition">¶</a></dt> <dd><p>Parse a <tt class="file docutils literal"><span class="pre">config.h</span></tt>-style file.</p> <p><em>fp</em> is a file-like object pointing to the <tt class="file docutils literal"><span class="pre">config.h</span></tt>-like file.</p> <p>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.</p> </dd></dl> <dl class="function"> <dt id="sysconfig.get_config_h_filename"> <tt class="descclassname">sysconfig.</tt><tt class="descname">get_config_h_filename</tt><big>(</big><big>)</big><a class="headerlink" href="#sysconfig.get_config_h_filename" title="Permalink to this definition">¶</a></dt> <dd><p>Return the path of <tt class="file docutils literal"><span class="pre">pyconfig.h</span></tt>.</p> </dd></dl> </div> </div> </div> </div> </div> <div class="sphinxsidebar"> <div class="sphinxsidebarwrapper"> <h3><a href="../contents.html">Table Of Contents</a></h3> <ul> <li><a class="reference internal" href="#">27.2. <tt class="docutils literal"><span class="pre">sysconfig</span></tt> — Provide access to Python’s configuration information</a><ul> <li><a class="reference internal" href="#configuration-variables">27.2.1. Configuration variables</a></li> <li><a class="reference internal" href="#installation-paths">27.2.2. Installation paths</a></li> <li><a class="reference internal" href="#other-functions">27.2.3. Other functions</a></li> </ul> </li> </ul> <h4>Previous topic</h4> <p class="topless"><a href="sys.html" title="previous chapter">27.1. <tt class="docutils literal"><span class="pre">sys</span></tt> — System-specific parameters and functions</a></p> <h4>Next topic</h4> <p class="topless"><a href="__builtin__.html" title="next chapter">27.3. <tt class="docutils literal"><span class="pre">__builtin__</span></tt> — Built-in objects</a></p> <h3>This Page</h3> <ul class="this-page-menu"> <li><a href="../bugs.html">Report a Bug</a></li> <li><a href="../_sources/library/sysconfig.txt" rel="nofollow">Show Source</a></li> </ul> <div id="searchbox" style="display: none"> <h3>Quick search</h3> <form class="search" action="../search.html" method="get"> <input type="text" name="q" /> <input type="submit" value="Go" /> <input type="hidden" name="check_keywords" value="yes" /> <input type="hidden" name="area" value="default" /> </form> <p class="searchtip" style="font-size: 90%"> Enter search terms or a module, class or function name. </p> </div> <script type="text/javascript">$('#searchbox').show(0);</script> </div> </div> <div class="clearer"></div> </div> <div class="related"> <h3>Navigation</h3> <ul> <li class="right" style="margin-right: 10px"> <a href="../genindex.html" title="General Index" >index</a></li> <li class="right" > <a href="../py-modindex.html" title="Python Module Index" >modules</a> |</li> <li class="right" > <a href="__builtin__.html" title="27.3. __builtin__ — Built-in objects" >next</a> |</li> <li class="right" > <a href="sys.html" title="27.1. sys — System-specific parameters and functions" >previous</a> |</li> <li><img src="../_static/py.png" alt="" style="vertical-align: middle; margin-top: -1px"/></li> <li><a href="http://www.python.org/">Python</a> »</li> <li> <a href="../index.html">Python 2.7.5 documentation</a> » </li> <li><a href="index.html" >The Python Standard Library</a> »</li> <li><a href="python.html" >27. Python Runtime Services</a> »</li> </ul> </div> <div class="footer"> © <a href="../copyright.html">Copyright</a> 1990-2020, Python Software Foundation. <br /> The Python Software Foundation is a non-profit corporation. <a href="http://www.python.org/psf/donations/">Please donate.</a> <br /> Last updated on Oct 13, 2020. <a href="../bugs.html">Found a bug</a>? <br /> Created using <a href="http://sphinx.pocoo.org/">Sphinx</a> 1.1.3. </div> </body> </html>