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<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="c.Py_FdIsInteractive">
int <code class="descname">Py_FdIsInteractive</code><span class="sig-paren">(</span>FILE<em> *fp</em>, const char<em> *filename</em><span class="sig-paren">)</span><a class="headerlink" href="#c.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 <code class="docutils literal notranslate"><span class="pre">isatty(fileno(fp))</span></code>
is true. If the global flag <code class="xref c c-data docutils literal notranslate"><span class="pre">Py_InteractiveFlag</span></code> 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 <code class="docutils literal notranslate"><span class="pre">'<stdin>'</span></code> or <code class="docutils literal notranslate"><span class="pre">'???'</span></code>.</p>
</dd></dl>
<dl class="function">
<dt id="c.PyOS_AfterFork">
void <code class="descname">PyOS_AfterFork</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#c.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="c.PyOS_CheckStack">
int <code class="descname">PyOS_CheckStack</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#c.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 <code class="xref py py-const docutils literal notranslate"><span class="pre">USE_STACKCHECK</span></code> is defined (currently
on Windows using the Microsoft Visual C++ compiler). <code class="xref py py-const docutils literal notranslate"><span class="pre">USE_STACKCHECK</span></code>
will be defined automatically; you should never change the definition in your
own code.</p>
</dd></dl>
<dl class="function">
<dt id="c.PyOS_getsig">
PyOS_sighandler_t <code class="descname">PyOS_getsig</code><span class="sig-paren">(</span>int<em> i</em><span class="sig-paren">)</span><a class="headerlink" href="#c.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 <code class="xref c c-func docutils literal notranslate"><span class="pre">sigaction()</span></code> or <code class="xref c c-func docutils literal notranslate"><span class="pre">signal()</span></code>. Do not call those functions
directly! <code class="xref c c-type docutils literal notranslate"><span class="pre">PyOS_sighandler_t</span></code> is a typedef alias for <code class="xref c c-type docutils literal notranslate"><span class="pre">void</span>
<span class="pre">(*)(int)</span></code>.</p>
</dd></dl>
<dl class="function">
<dt id="c.PyOS_setsig">
PyOS_sighandler_t <code class="descname">PyOS_setsig</code><span class="sig-paren">(</span>int<em> i</em>, PyOS_sighandler_t<em> h</em><span class="sig-paren">)</span><a class="headerlink" href="#c.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 <code class="xref c c-func docutils literal notranslate"><span class="pre">sigaction()</span></code> or <code class="xref c c-func docutils literal notranslate"><span class="pre">signal()</span></code>. Do
not call those functions directly! <code class="xref c c-type docutils literal notranslate"><span class="pre">PyOS_sighandler_t</span></code> is a typedef
alias for <code class="xref c c-type docutils literal notranslate"><span class="pre">void</span> <span class="pre">(*)(int)</span></code>.</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."><code class="xref py py-mod docutils literal notranslate"><span class="pre">sys</span></code></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."><code class="xref py py-mod docutils literal notranslate"><span class="pre">sys</span></code></a> module’s dict, which is contained in the internal thread state structure.</p>
<dl class="function">
<dt id="c.PySys_GetObject">
<a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a> *<code class="descname">PySys_GetObject</code><span class="sig-paren">(</span>char<em> *name</em><span class="sig-paren">)</span><a class="headerlink" href="#c.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."><code class="xref py py-mod docutils literal notranslate"><span class="pre">sys</span></code></a> module or <em>NULL</em> if it does
not exist, without setting an exception.</p>
</dd></dl>
<dl class="function">
<dt id="c.PySys_GetFile">
FILE *<code class="descname">PySys_GetFile</code><span class="sig-paren">(</span>char<em> *name</em>, FILE<em> *def</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PySys_GetFile" title="Permalink to this definition">¶</a></dt>
<dd><p>Return the <code class="xref c c-type docutils literal notranslate"><span class="pre">FILE*</span></code> 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."><code class="xref py py-mod docutils literal notranslate"><span class="pre">sys</span></code></a> module, or <em>def</em> if <em>name</em> is not in the module or is not associated
with a <code class="xref c c-type docutils literal notranslate"><span class="pre">FILE*</span></code>.</p>
</dd></dl>
<dl class="function">
<dt id="c.PySys_SetObject">
int <code class="descname">PySys_SetObject</code><span class="sig-paren">(</span>char<em> *name</em>, <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *v</em><span class="sig-paren">)</span><a class="headerlink" href="#c.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."><code class="xref py py-mod docutils literal notranslate"><span class="pre">sys</span></code></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 <code class="docutils literal notranslate"><span class="pre">0</span></code> on success, <code class="docutils literal notranslate"><span class="pre">-1</span></code>
on error.</p>
</dd></dl>
<dl class="function">
<dt id="c.PySys_ResetWarnOptions">
void <code class="descname">PySys_ResetWarnOptions</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#c.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"><code class="xref py py-data docutils literal notranslate"><span class="pre">sys.warnoptions</span></code></a> to an empty list.</p>
</dd></dl>
<dl class="function">
<dt id="c.PySys_AddWarnOption">
void <code class="descname">PySys_AddWarnOption</code><span class="sig-paren">(</span>char<em> *s</em><span class="sig-paren">)</span><a class="headerlink" href="#c.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"><code class="xref py py-data docutils literal notranslate"><span class="pre">sys.warnoptions</span></code></a>.</p>
</dd></dl>
<dl class="function">
<dt id="c.PySys_SetPath">
void <code class="descname">PySys_SetPath</code><span class="sig-paren">(</span>char<em> *path</em><span class="sig-paren">)</span><a class="headerlink" href="#c.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"><code class="xref py py-data docutils literal notranslate"><span class="pre">sys.path</span></code></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
(<code class="docutils literal notranslate"><span class="pre">:</span></code> on Unix, <code class="docutils literal notranslate"><span class="pre">;</span></code> on Windows).</p>
</dd></dl>
<dl class="function">
<dt id="c.PySys_WriteStdout">
void <code class="descname">PySys_WriteStdout</code><span class="sig-paren">(</span>const char<em> *format</em>, ...<span class="sig-paren">)</span><a class="headerlink" href="#c.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"><code class="xref py py-data docutils literal notranslate"><span class="pre">sys.stdout</span></code></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"><code class="xref py py-data docutils literal notranslate"><span class="pre">sys.stdout</span></code></a> is unset, the formatted message
is written to the real (C level) <em>stdout</em>.</p>
</dd></dl>
<dl class="function">
<dt id="c.PySys_WriteStderr">
void <code class="descname">PySys_WriteStderr</code><span class="sig-paren">(</span>const char<em> *format</em>, ...<span class="sig-paren">)</span><a class="headerlink" href="#c.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"><code class="xref py py-data docutils literal notranslate"><span class="pre">sys.stderr</span></code></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="c.Py_FatalError">
void <code class="descname">Py_FatalError</code><span class="sig-paren">(</span>const char<em> *message</em><span class="sig-paren">)</span><a class="headerlink" href="#c.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 <code class="xref c c-func docutils literal notranslate"><span class="pre">abort()</span></code> is called which will attempt to produce a <code class="file docutils literal notranslate"><span class="pre">core</span></code>
file.</p>
</dd></dl>
<dl class="function">
<dt id="c.Py_Exit">
void <code class="descname">Py_Exit</code><span class="sig-paren">(</span>int<em> status</em><span class="sig-paren">)</span><a class="headerlink" href="#c.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#c.Py_Finalize" title="Py_Finalize"><code class="xref c c-func docutils literal notranslate"><span class="pre">Py_Finalize()</span></code></a> and then calls the
standard C library function <code class="docutils literal notranslate"><span class="pre">exit(status)</span></code>.</p>
</dd></dl>
<dl class="function">
<dt id="c.Py_AtExit">
int <code class="descname">Py_AtExit</code><span class="sig-paren">(</span>void (<em>*func</em>)()<span class="sig-paren">)</span><a class="headerlink" href="#c.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#c.Py_Finalize" title="Py_Finalize"><code class="xref c c-func docutils literal notranslate"><span class="pre">Py_Finalize()</span></code></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="#c.Py_AtExit" title="Py_AtExit"><code class="xref c c-func docutils literal notranslate"><span class="pre">Py_AtExit()</span></code></a> returns <code class="docutils literal notranslate"><span class="pre">0</span></code>; on failure, it returns <code class="docutils literal notranslate"><span class="pre">-1</span></code>. 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>
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<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>
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title="next chapter">Importing Modules</a></p>
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