Edit File: sys.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>Operating System Utilities — 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="Utilities" href="utilities.html" /> <link rel="next" title="Importing Modules" href="import.html" /> <link rel="prev" title="Utilities" href="utilities.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="import.html" title="Importing Modules" accesskey="N">next</a> |</li> <li class="right" > <a href="utilities.html" title="Utilities" 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" >Python/C API Reference Manual</a> »</li> <li><a href="utilities.html" accesskey="U">Utilities</a> »</li> </ul> </div> <div class="document"> <div class="documentwrapper"> <div class="bodywrapper"> <div class="body"> <div class="section" id="operating-system-utilities"> <span id="os"></span><h1>Operating System Utilities<a class="headerlink" href="#operating-system-utilities" title="Permalink to this headline">¶</a></h1> <dl class="function"> <dt id="Py_FdIsInteractive"> int <tt class="descname">Py_FdIsInteractive</tt><big>(</big>FILE<em> *fp</em>, const char<em> *filename</em><big>)</big><a class="headerlink" href="#Py_FdIsInteractive" title="Permalink to this definition">¶</a></dt> <dd><p>Return true (nonzero) if the standard I/O file <em>fp</em> with name <em>filename</em> is deemed interactive. This is the case for files for which <tt class="docutils literal"><span class="pre">isatty(fileno(fp))</span></tt> is true. If the global flag <tt class="xref c c-data docutils literal"><span class="pre">Py_InteractiveFlag</span></tt> is true, this function also returns true if the <em>filename</em> pointer is <em>NULL</em> or if the name is equal to one of the strings <tt class="docutils literal"><span class="pre">'<stdin>'</span></tt> or <tt class="docutils literal"><span class="pre">'???'</span></tt>.</p> </dd></dl> <dl class="function"> <dt id="PyOS_AfterFork"> void <tt class="descname">PyOS_AfterFork</tt><big>(</big><big>)</big><a class="headerlink" href="#PyOS_AfterFork" title="Permalink to this definition">¶</a></dt> <dd><p>Function to update some internal state after a process fork; this should be called in the new process if the Python interpreter will continue to be used. If a new executable is loaded into the new process, this function does not need to be called.</p> </dd></dl> <dl class="function"> <dt id="PyOS_CheckStack"> int <tt class="descname">PyOS_CheckStack</tt><big>(</big><big>)</big><a class="headerlink" href="#PyOS_CheckStack" title="Permalink to this definition">¶</a></dt> <dd><p>Return true when the interpreter runs out of stack space. This is a reliable check, but is only available when <tt class="xref py py-const docutils literal"><span class="pre">USE_STACKCHECK</span></tt> is defined (currently on Windows using the Microsoft Visual C++ compiler). <tt class="xref py py-const docutils literal"><span class="pre">USE_STACKCHECK</span></tt> will be defined automatically; you should never change the definition in your own code.</p> </dd></dl> <dl class="function"> <dt id="PyOS_getsig"> PyOS_sighandler_t <tt class="descname">PyOS_getsig</tt><big>(</big>int<em> i</em><big>)</big><a class="headerlink" href="#PyOS_getsig" title="Permalink to this definition">¶</a></dt> <dd><p>Return the current signal handler for signal <em>i</em>. This is a thin wrapper around either <tt class="xref c c-func docutils literal"><span class="pre">sigaction()</span></tt> or <tt class="xref c c-func docutils literal"><span class="pre">signal()</span></tt>. Do not call those functions directly! <tt class="xref c c-type docutils literal"><span class="pre">PyOS_sighandler_t</span></tt> is a typedef alias for <tt class="xref c c-type docutils literal"><span class="pre">void</span> <span class="pre">(*)(int)</span></tt>.</p> </dd></dl> <dl class="function"> <dt id="PyOS_setsig"> PyOS_sighandler_t <tt class="descname">PyOS_setsig</tt><big>(</big>int<em> i</em>, PyOS_sighandler_t<em> h</em><big>)</big><a class="headerlink" href="#PyOS_setsig" title="Permalink to this definition">¶</a></dt> <dd><p>Set the signal handler for signal <em>i</em> to be <em>h</em>; return the old signal handler. This is a thin wrapper around either <tt class="xref c c-func docutils literal"><span class="pre">sigaction()</span></tt> or <tt class="xref c c-func docutils literal"><span class="pre">signal()</span></tt>. Do not call those functions directly! <tt class="xref c c-type docutils literal"><span class="pre">PyOS_sighandler_t</span></tt> is a typedef alias for <tt class="xref c c-type docutils literal"><span class="pre">void</span> <span class="pre">(*)(int)</span></tt>.</p> </dd></dl> </div> <div class="section" id="system-functions"> <span id="systemfunctions"></span><h1>System Functions<a class="headerlink" href="#system-functions" title="Permalink to this headline">¶</a></h1> <p>These are utility functions that make functionality from the <a class="reference internal" href="../library/sys.html#module-sys" title="sys: Access system-specific parameters and functions."><tt class="xref py py-mod docutils literal"><span class="pre">sys</span></tt></a> module accessible to C code. They all work with the current interpreter thread’s <a class="reference internal" href="../library/sys.html#module-sys" title="sys: Access system-specific parameters and functions."><tt class="xref py py-mod docutils literal"><span class="pre">sys</span></tt></a> module’s dict, which is contained in the internal thread state structure.</p> <dl class="function"> <dt id="PySys_GetObject"> <a class="reference internal" href="structures.html#PyObject" title="PyObject">PyObject</a> *<tt class="descname">PySys_GetObject</tt><big>(</big>char<em> *name</em><big>)</big><a class="headerlink" href="#PySys_GetObject" title="Permalink to this definition">¶</a></dt> <dd><em class="refcount">Return value: Borrowed reference.</em><p>Return the object <em>name</em> from the <a class="reference internal" href="../library/sys.html#module-sys" title="sys: Access system-specific parameters and functions."><tt class="xref py py-mod docutils literal"><span class="pre">sys</span></tt></a> module or <em>NULL</em> if it does not exist, without setting an exception.</p> </dd></dl> <dl class="function"> <dt id="PySys_GetFile"> FILE *<tt class="descname">PySys_GetFile</tt><big>(</big>char<em> *name</em>, FILE<em> *def</em><big>)</big><a class="headerlink" href="#PySys_GetFile" title="Permalink to this definition">¶</a></dt> <dd><p>Return the <tt class="xref c c-type docutils literal"><span class="pre">FILE*</span></tt> associated with the object <em>name</em> in the <a class="reference internal" href="../library/sys.html#module-sys" title="sys: Access system-specific parameters and functions."><tt class="xref py py-mod docutils literal"><span class="pre">sys</span></tt></a> module, or <em>def</em> if <em>name</em> is not in the module or is not associated with a <tt class="xref c c-type docutils literal"><span class="pre">FILE*</span></tt>.</p> </dd></dl> <dl class="function"> <dt id="PySys_SetObject"> int <tt class="descname">PySys_SetObject</tt><big>(</big>char<em> *name</em>, <a class="reference internal" href="structures.html#PyObject" title="PyObject">PyObject</a><em> *v</em><big>)</big><a class="headerlink" href="#PySys_SetObject" title="Permalink to this definition">¶</a></dt> <dd><p>Set <em>name</em> in the <a class="reference internal" href="../library/sys.html#module-sys" title="sys: Access system-specific parameters and functions."><tt class="xref py py-mod docutils literal"><span class="pre">sys</span></tt></a> module to <em>v</em> unless <em>v</em> is <em>NULL</em>, in which case <em>name</em> is deleted from the sys module. Returns <tt class="docutils literal"><span class="pre">0</span></tt> on success, <tt class="docutils literal"><span class="pre">-1</span></tt> on error.</p> </dd></dl> <dl class="function"> <dt id="PySys_ResetWarnOptions"> void <tt class="descname">PySys_ResetWarnOptions</tt><big>(</big><big>)</big><a class="headerlink" href="#PySys_ResetWarnOptions" title="Permalink to this definition">¶</a></dt> <dd><p>Reset <a class="reference internal" href="../library/sys.html#sys.warnoptions" title="sys.warnoptions"><tt class="xref py py-data docutils literal"><span class="pre">sys.warnoptions</span></tt></a> to an empty list.</p> </dd></dl> <dl class="function"> <dt id="PySys_AddWarnOption"> void <tt class="descname">PySys_AddWarnOption</tt><big>(</big>char<em> *s</em><big>)</big><a class="headerlink" href="#PySys_AddWarnOption" title="Permalink to this definition">¶</a></dt> <dd><p>Append <em>s</em> to <a class="reference internal" href="../library/sys.html#sys.warnoptions" title="sys.warnoptions"><tt class="xref py py-data docutils literal"><span class="pre">sys.warnoptions</span></tt></a>.</p> </dd></dl> <dl class="function"> <dt id="PySys_SetPath"> void <tt class="descname">PySys_SetPath</tt><big>(</big>char<em> *path</em><big>)</big><a class="headerlink" href="#PySys_SetPath" title="Permalink to this definition">¶</a></dt> <dd><p>Set <a class="reference internal" href="../library/sys.html#sys.path" title="sys.path"><tt class="xref py py-data docutils literal"><span class="pre">sys.path</span></tt></a> to a list object of paths found in <em>path</em> which should be a list of paths separated with the platform’s search path delimiter (<tt class="docutils literal"><span class="pre">:</span></tt> on Unix, <tt class="docutils literal"><span class="pre">;</span></tt> on Windows).</p> </dd></dl> <dl class="function"> <dt id="PySys_WriteStdout"> void <tt class="descname">PySys_WriteStdout</tt><big>(</big>const char<em> *format</em>, ...<big>)</big><a class="headerlink" href="#PySys_WriteStdout" title="Permalink to this definition">¶</a></dt> <dd><p>Write the output string described by <em>format</em> to <a class="reference internal" href="../library/sys.html#sys.stdout" title="sys.stdout"><tt class="xref py py-data docutils literal"><span class="pre">sys.stdout</span></tt></a>. No exceptions are raised, even if truncation occurs (see below).</p> <p><em>format</em> should limit the total size of the formatted output string to 1000 bytes or less – after 1000 bytes, the output string is truncated. In particular, this means that no unrestricted “%s” formats should occur; these should be limited using “%.<N>s” where <N> is a decimal number calculated so that <N> plus the maximum size of other formatted text does not exceed 1000 bytes. Also watch out for “%f”, which can print hundreds of digits for very large numbers.</p> <p>If a problem occurs, or <a class="reference internal" href="../library/sys.html#sys.stdout" title="sys.stdout"><tt class="xref py py-data docutils literal"><span class="pre">sys.stdout</span></tt></a> is unset, the formatted message is written to the real (C level) <em>stdout</em>.</p> </dd></dl> <dl class="function"> <dt id="PySys_WriteStderr"> void <tt class="descname">PySys_WriteStderr</tt><big>(</big>const char<em> *format</em>, ...<big>)</big><a class="headerlink" href="#PySys_WriteStderr" title="Permalink to this definition">¶</a></dt> <dd><p>As above, but write to <a class="reference internal" href="../library/sys.html#sys.stderr" title="sys.stderr"><tt class="xref py py-data docutils literal"><span class="pre">sys.stderr</span></tt></a> or <em>stderr</em> instead.</p> </dd></dl> </div> <div class="section" id="process-control"> <span id="processcontrol"></span><h1>Process Control<a class="headerlink" href="#process-control" title="Permalink to this headline">¶</a></h1> <dl class="function"> <dt id="Py_FatalError"> void <tt class="descname">Py_FatalError</tt><big>(</big>const char<em> *message</em><big>)</big><a class="headerlink" href="#Py_FatalError" title="Permalink to this definition">¶</a></dt> <dd><p id="index-0">Print a fatal error message and kill the process. No cleanup is performed. This function should only be invoked when a condition is detected that would make it dangerous to continue using the Python interpreter; e.g., when the object administration appears to be corrupted. On Unix, the standard C library function <tt class="xref c c-func docutils literal"><span class="pre">abort()</span></tt> is called which will attempt to produce a <tt class="file docutils literal"><span class="pre">core</span></tt> file.</p> </dd></dl> <dl class="function"> <dt id="Py_Exit"> void <tt class="descname">Py_Exit</tt><big>(</big>int<em> status</em><big>)</big><a class="headerlink" href="#Py_Exit" title="Permalink to this definition">¶</a></dt> <dd><p id="index-1">Exit the current process. This calls <a class="reference internal" href="init.html#Py_Finalize" title="Py_Finalize"><tt class="xref c c-func docutils literal"><span class="pre">Py_Finalize()</span></tt></a> and then calls the standard C library function <tt class="docutils literal"><span class="pre">exit(status)</span></tt>.</p> </dd></dl> <dl class="function"> <dt id="Py_AtExit"> int <tt class="descname">Py_AtExit</tt><big>(</big>void (*func)<em> ()</em><big>)</big><a class="headerlink" href="#Py_AtExit" title="Permalink to this definition">¶</a></dt> <dd><p id="index-2">Register a cleanup function to be called by <a class="reference internal" href="init.html#Py_Finalize" title="Py_Finalize"><tt class="xref c c-func docutils literal"><span class="pre">Py_Finalize()</span></tt></a>. The cleanup function will be called with no arguments and should return no value. At most 32 cleanup functions can be registered. When the registration is successful, <a class="reference internal" href="#Py_AtExit" title="Py_AtExit"><tt class="xref c c-func docutils literal"><span class="pre">Py_AtExit()</span></tt></a> returns <tt class="docutils literal"><span class="pre">0</span></tt>; on failure, it returns <tt class="docutils literal"><span class="pre">-1</span></tt>. The cleanup function registered last is called first. Each cleanup function will be called at most once. Since Python’s internal finalization will have completed before the cleanup function, no Python APIs should be called by <em>func</em>.</p> </dd></dl> </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="#">Operating System Utilities</a></li> <li><a class="reference internal" href="#system-functions">System Functions</a></li> <li><a class="reference internal" href="#process-control">Process Control</a></li> </ul> <h4>Previous topic</h4> <p class="topless"><a href="utilities.html" title="previous chapter">Utilities</a></p> <h4>Next topic</h4> <p class="topless"><a href="import.html" title="next chapter">Importing Modules</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/c-api/sys.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="import.html" title="Importing Modules" >next</a> |</li> <li class="right" > <a href="utilities.html" title="Utilities" >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" >Python/C API Reference Manual</a> »</li> <li><a href="utilities.html" >Utilities</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>