View file File name : contextvars.html Content : <!DOCTYPE html> <html> <head> <meta charset="utf-8" /> <meta name="viewport" content="width=device-width, initial-scale=1.0" /><meta name="generator" content="Docutils 0.17.1: http://docutils.sourceforge.net/" /> <title>Context Variables Objects — Python 3.10.12 documentation</title><meta name="viewport" content="width=device-width, initial-scale=1.0"> <link rel="stylesheet" type="text/css" href="../_static/pygments.css" /> <link rel="stylesheet" type="text/css" href="../_static/pydoctheme.css?2022.1" /> <script data-url_root="../" id="documentation_options" src="../_static/documentation_options.js"></script> <script src="../_static/jquery.js"></script> <script src="../_static/underscore.js"></script> <script src="../_static/doctools.js"></script> <script src="../_static/sidebar.js"></script> <link rel="search" type="application/opensearchdescription+xml" title="Search within Python 3.10.12 documentation" href="../_static/opensearch.xml"/> <link rel="author" title="About these documents" href="../about.html" /> <link rel="index" title="Index" href="../genindex.html" /> <link rel="search" title="Search" href="../search.html" /> <link rel="copyright" title="Copyright" href="../copyright.html" /> <link rel="next" title="DateTime Objects" href="datetime.html" /> <link rel="prev" title="Coroutine Objects" href="coro.html" /> <link rel="canonical" href="file:///usr/share/doc/python3.10/html/c-api/contextvars.html" /> <style> @media only screen { table.full-width-table { width: 100%; } } </style> <link rel="shortcut icon" type="image/png" href="../_static/py.svg" /> <script type="text/javascript" src="../_static/copybutton.js"></script> <script type="text/javascript" src="../_static/menu.js"></script> </head> <body> <div class="mobile-nav"> <input type="checkbox" id="menuToggler" class="toggler__input" aria-controls="navigation" aria-pressed="false" aria-expanded="false" role="button" aria-label="Menu" /> <label for="menuToggler" class="toggler__label"> <span></span> </label> <nav class="nav-content" role="navigation"> <a href="https://www.python.org/" class="nav-logo"> <img src="../_static/py.svg" alt="Logo"/> </a> <div class="version_switcher_placeholder"></div> <form role="search" class="search" action="../search.html" method="get"> <svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" class="search-icon"> <path fill-rule="nonzero" d="M15.5 14h-.79l-.28-.27a6.5 6.5 0 001.48-5.34c-.47-2.78-2.79-5-5.59-5.34a6.505 6.505 0 00-7.27 7.27c.34 2.8 2.56 5.12 5.34 5.59a6.5 6.5 0 005.34-1.48l.27.28v.79l4.25 4.25c.41.41 1.08.41 1.49 0 .41-.41.41-1.08 0-1.49L15.5 14zm-6 0C7.01 14 5 11.99 5 9.5S7.01 5 9.5 5 14 7.01 14 9.5 11.99 14 9.5 14z" fill="#444"></path> </svg> <input type="text" name="q" aria-label="Quick search"/> <input type="submit" value="Go"/> </form> </nav> <div class="menu-wrapper"> <nav class="menu" role="navigation" aria-label="main navigation"> <div class="language_switcher_placeholder"></div> <h4>Previous topic</h4> <p class="topless"><a href="coro.html" title="previous chapter">Coroutine Objects</a></p> <h4>Next topic</h4> <p class="topless"><a href="datetime.html" title="next chapter">DateTime Objects</a></p> <div role="note" aria-label="source link"> <h3>This Page</h3> <ul class="this-page-menu"> <li><a href="../bugs.html">Report a Bug</a></li> <li> <a href="https://github.com/python/cpython/blob/3.10/Doc/c-api/contextvars.rst" rel="nofollow">Show Source </a> </li> </ul> </div> </nav> </div> </div> <div class="related" role="navigation" aria-label="related navigation"> <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="datetime.html" title="DateTime Objects" accesskey="N">next</a> |</li> <li class="right" > <a href="coro.html" title="Coroutine Objects" accesskey="P">previous</a> |</li> <li><img src="../_static/py.svg" alt="python logo" style="vertical-align: middle; margin-top: -1px"/></li> <li><a href="https://www.python.org/">Python</a> »</li> <li class="switchers"> <div class="language_switcher_placeholder"></div> <div class="version_switcher_placeholder"></div> </li> <li> </li> <li id="cpython-language-and-version"> <a href="../index.html">3.10.12 Documentation</a> » </li> <li class="nav-item nav-item-1"><a href="index.html" >Python/C API Reference Manual</a> »</li> <li class="nav-item nav-item-2"><a href="concrete.html" accesskey="U">Concrete Objects Layer</a> »</li> <li class="nav-item nav-item-this"><a href="">Context Variables Objects</a></li> <li class="right"> <div class="inline-search" role="search"> <form class="inline-search" action="../search.html" method="get"> <input placeholder="Quick search" aria-label="Quick search" 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> </div> | </li> </ul> </div> <div class="document"> <div class="documentwrapper"> <div class="bodywrapper"> <div class="body" role="main"> <section id="context-variables-objects"> <span id="contextvarsobjects"></span><h1>Context Variables Objects<a class="headerlink" href="#context-variables-objects" title="Permalink to this headline">¶</a></h1> <div class="versionchanged" id="contextvarsobjects-pointertype-change"> <p><span class="versionmodified changed">Changed in version 3.7.1: </span></p> <div class="admonition note"> <p class="admonition-title">Note</p> <p>In Python 3.7.1 the signatures of all context variables C APIs were <strong>changed</strong> to use <a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><code class="xref c c-type docutils literal notranslate"><span class="pre">PyObject</span></code></a> pointers instead of <a class="reference internal" href="#c.PyContext" title="PyContext"><code class="xref c c-type docutils literal notranslate"><span class="pre">PyContext</span></code></a>, <a class="reference internal" href="#c.PyContextVar" title="PyContextVar"><code class="xref c c-type docutils literal notranslate"><span class="pre">PyContextVar</span></code></a>, and <a class="reference internal" href="#c.PyContextToken" title="PyContextToken"><code class="xref c c-type docutils literal notranslate"><span class="pre">PyContextToken</span></code></a>, e.g.:</p> <div class="highlight-c notranslate"><div class="highlight"><pre><span></span><span class="c1">// in 3.7.0:</span> <span class="n">PyContext</span><span class="w"> </span><span class="o">*</span><span class="nf">PyContext_New</span><span class="p">(</span><span class="kt">void</span><span class="p">);</span><span class="w"></span> <span class="c1">// in 3.7.1+:</span> <span class="n">PyObject</span><span class="w"> </span><span class="o">*</span><span class="nf">PyContext_New</span><span class="p">(</span><span class="kt">void</span><span class="p">);</span><span class="w"></span> </pre></div> </div> <p>See <a class="reference external" href="https://bugs.python.org/issue?@action=redirect&bpo=34762">bpo-34762</a> for more details.</p> </div> </div> <div class="versionadded"> <p><span class="versionmodified added">New in version 3.7.</span></p> </div> <p>This section details the public C API for the <a class="reference internal" href="../library/contextvars.html#module-contextvars" title="contextvars: Context Variables"><code class="xref py py-mod docutils literal notranslate"><span class="pre">contextvars</span></code></a> module.</p> <dl class="c type"> <dt class="sig sig-object c" id="c.PyContext"> <span class="k"><span class="pre">type</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyContext</span></span></span><a class="headerlink" href="#c.PyContext" title="Permalink to this definition">¶</a><br /></dt> <dd><p>The C structure used to represent a <a class="reference internal" href="../library/contextvars.html#contextvars.Context" title="contextvars.Context"><code class="xref py py-class docutils literal notranslate"><span class="pre">contextvars.Context</span></code></a> object.</p> </dd></dl> <dl class="c type"> <dt class="sig sig-object c" id="c.PyContextVar"> <span class="k"><span class="pre">type</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyContextVar</span></span></span><a class="headerlink" href="#c.PyContextVar" title="Permalink to this definition">¶</a><br /></dt> <dd><p>The C structure used to represent a <a class="reference internal" href="../library/contextvars.html#contextvars.ContextVar" title="contextvars.ContextVar"><code class="xref py py-class docutils literal notranslate"><span class="pre">contextvars.ContextVar</span></code></a> object.</p> </dd></dl> <dl class="c type"> <dt class="sig sig-object c" id="c.PyContextToken"> <span class="k"><span class="pre">type</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyContextToken</span></span></span><a class="headerlink" href="#c.PyContextToken" title="Permalink to this definition">¶</a><br /></dt> <dd><p>The C structure used to represent a <a class="reference internal" href="../library/contextvars.html#contextvars.Token" title="contextvars.Token"><code class="xref py py-class docutils literal notranslate"><span class="pre">contextvars.Token</span></code></a> object.</p> </dd></dl> <dl class="c var"> <dt class="sig sig-object c" id="c.PyContext_Type"> <a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject"><span class="n"><span class="pre">PyTypeObject</span></span></a><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyContext_Type</span></span></span><a class="headerlink" href="#c.PyContext_Type" title="Permalink to this definition">¶</a><br /></dt> <dd><p>The type object representing the <em>context</em> type.</p> </dd></dl> <dl class="c var"> <dt class="sig sig-object c" id="c.PyContextVar_Type"> <a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject"><span class="n"><span class="pre">PyTypeObject</span></span></a><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyContextVar_Type</span></span></span><a class="headerlink" href="#c.PyContextVar_Type" title="Permalink to this definition">¶</a><br /></dt> <dd><p>The type object representing the <em>context variable</em> type.</p> </dd></dl> <dl class="c var"> <dt class="sig sig-object c" id="c.PyContextToken_Type"> <a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject"><span class="n"><span class="pre">PyTypeObject</span></span></a><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyContextToken_Type</span></span></span><a class="headerlink" href="#c.PyContextToken_Type" title="Permalink to this definition">¶</a><br /></dt> <dd><p>The type object representing the <em>context variable token</em> type.</p> </dd></dl> <p>Type-check macros:</p> <dl class="c function"> <dt class="sig sig-object c" id="c.PyContext_CheckExact"> <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyContext_CheckExact</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">o</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyContext_CheckExact" title="Permalink to this definition">¶</a><br /></dt> <dd><p>Return true if <em>o</em> is of type <a class="reference internal" href="#c.PyContext_Type" title="PyContext_Type"><code class="xref c c-data docutils literal notranslate"><span class="pre">PyContext_Type</span></code></a>. <em>o</em> must not be <code class="docutils literal notranslate"><span class="pre">NULL</span></code>. This function always succeeds.</p> </dd></dl> <dl class="c function"> <dt class="sig sig-object c" id="c.PyContextVar_CheckExact"> <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyContextVar_CheckExact</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">o</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyContextVar_CheckExact" title="Permalink to this definition">¶</a><br /></dt> <dd><p>Return true if <em>o</em> is of type <a class="reference internal" href="#c.PyContextVar_Type" title="PyContextVar_Type"><code class="xref c c-data docutils literal notranslate"><span class="pre">PyContextVar_Type</span></code></a>. <em>o</em> must not be <code class="docutils literal notranslate"><span class="pre">NULL</span></code>. This function always succeeds.</p> </dd></dl> <dl class="c function"> <dt class="sig sig-object c" id="c.PyContextToken_CheckExact"> <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyContextToken_CheckExact</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">o</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyContextToken_CheckExact" title="Permalink to this definition">¶</a><br /></dt> <dd><p>Return true if <em>o</em> is of type <a class="reference internal" href="#c.PyContextToken_Type" title="PyContextToken_Type"><code class="xref c c-data docutils literal notranslate"><span class="pre">PyContextToken_Type</span></code></a>. <em>o</em> must not be <code class="docutils literal notranslate"><span class="pre">NULL</span></code>. This function always succeeds.</p> </dd></dl> <p>Context object management functions:</p> <dl class="c function"> <dt class="sig sig-object c" id="c.PyContext_New"> <a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="sig-name descname"><span class="n"><span class="pre">PyContext_New</span></span></span><span class="sig-paren">(</span><span class="kt"><span class="pre">void</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyContext_New" title="Permalink to this definition">¶</a><br /></dt> <dd><em class="refcount">Return value: New reference.</em><p>Create a new empty context object. Returns <code class="docutils literal notranslate"><span class="pre">NULL</span></code> if an error has occurred.</p> </dd></dl> <dl class="c function"> <dt class="sig sig-object c" id="c.PyContext_Copy"> <a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="sig-name descname"><span class="n"><span class="pre">PyContext_Copy</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">ctx</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyContext_Copy" title="Permalink to this definition">¶</a><br /></dt> <dd><em class="refcount">Return value: New reference.</em><p>Create a shallow copy of the passed <em>ctx</em> context object. Returns <code class="docutils literal notranslate"><span class="pre">NULL</span></code> if an error has occurred.</p> </dd></dl> <dl class="c function"> <dt class="sig sig-object c" id="c.PyContext_CopyCurrent"> <a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="sig-name descname"><span class="n"><span class="pre">PyContext_CopyCurrent</span></span></span><span class="sig-paren">(</span><span class="kt"><span class="pre">void</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyContext_CopyCurrent" title="Permalink to this definition">¶</a><br /></dt> <dd><em class="refcount">Return value: New reference.</em><p>Create a shallow copy of the current thread context. Returns <code class="docutils literal notranslate"><span class="pre">NULL</span></code> if an error has occurred.</p> </dd></dl> <dl class="c function"> <dt class="sig sig-object c" id="c.PyContext_Enter"> <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyContext_Enter</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">ctx</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyContext_Enter" title="Permalink to this definition">¶</a><br /></dt> <dd><p>Set <em>ctx</em> as the current context for the current thread. Returns <code class="docutils literal notranslate"><span class="pre">0</span></code> on success, and <code class="docutils literal notranslate"><span class="pre">-1</span></code> on error.</p> </dd></dl> <dl class="c function"> <dt class="sig sig-object c" id="c.PyContext_Exit"> <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyContext_Exit</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">ctx</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyContext_Exit" title="Permalink to this definition">¶</a><br /></dt> <dd><p>Deactivate the <em>ctx</em> context and restore the previous context as the current context for the current thread. Returns <code class="docutils literal notranslate"><span class="pre">0</span></code> on success, and <code class="docutils literal notranslate"><span class="pre">-1</span></code> on error.</p> </dd></dl> <p>Context variable functions:</p> <dl class="c function"> <dt class="sig sig-object c" id="c.PyContextVar_New"> <a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="sig-name descname"><span class="n"><span class="pre">PyContextVar_New</span></span></span><span class="sig-paren">(</span><span class="k"><span class="pre">const</span></span><span class="w"> </span><span class="kt"><span class="pre">char</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">name</span></span>, <a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">def</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyContextVar_New" title="Permalink to this definition">¶</a><br /></dt> <dd><em class="refcount">Return value: New reference.</em><p>Create a new <code class="docutils literal notranslate"><span class="pre">ContextVar</span></code> object. The <em>name</em> parameter is used for introspection and debug purposes. The <em>def</em> parameter specifies a default value for the context variable, or <code class="docutils literal notranslate"><span class="pre">NULL</span></code> for no default. If an error has occurred, this function returns <code class="docutils literal notranslate"><span class="pre">NULL</span></code>.</p> </dd></dl> <dl class="c function"> <dt class="sig sig-object c" id="c.PyContextVar_Get"> <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyContextVar_Get</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">var</span></span>, <a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">default_value</span></span>, <a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">value</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyContextVar_Get" title="Permalink to this definition">¶</a><br /></dt> <dd><p>Get the value of a context variable. Returns <code class="docutils literal notranslate"><span class="pre">-1</span></code> if an error has occurred during lookup, and <code class="docutils literal notranslate"><span class="pre">0</span></code> if no error occurred, whether or not a value was found.</p> <p>If the context variable was found, <em>value</em> will be a pointer to it. If the context variable was <em>not</em> found, <em>value</em> will point to:</p> <ul class="simple"> <li><p><em>default_value</em>, if not <code class="docutils literal notranslate"><span class="pre">NULL</span></code>;</p></li> <li><p>the default value of <em>var</em>, if not <code class="docutils literal notranslate"><span class="pre">NULL</span></code>;</p></li> <li><p><code class="docutils literal notranslate"><span class="pre">NULL</span></code></p></li> </ul> <p>Except for <code class="docutils literal notranslate"><span class="pre">NULL</span></code>, the function returns a new reference.</p> </dd></dl> <dl class="c function"> <dt class="sig sig-object c" id="c.PyContextVar_Set"> <a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="sig-name descname"><span class="n"><span class="pre">PyContextVar_Set</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">var</span></span>, <a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">value</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyContextVar_Set" title="Permalink to this definition">¶</a><br /></dt> <dd><em class="refcount">Return value: New reference.</em><p>Set the value of <em>var</em> to <em>value</em> in the current context. Returns a new token object for this change, or <code class="docutils literal notranslate"><span class="pre">NULL</span></code> if an error has occurred.</p> </dd></dl> <dl class="c function"> <dt class="sig sig-object c" id="c.PyContextVar_Reset"> <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyContextVar_Reset</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">var</span></span>, <a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">token</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyContextVar_Reset" title="Permalink to this definition">¶</a><br /></dt> <dd><p>Reset the state of the <em>var</em> context variable to that it was in before <a class="reference internal" href="#c.PyContextVar_Set" title="PyContextVar_Set"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyContextVar_Set()</span></code></a> that returned the <em>token</em> was called. This function returns <code class="docutils literal notranslate"><span class="pre">0</span></code> on success and <code class="docutils literal notranslate"><span class="pre">-1</span></code> on error.</p> </dd></dl> </section> <div class="clearer"></div> </div> </div> </div> <div class="sphinxsidebar" role="navigation" aria-label="main navigation"> <div class="sphinxsidebarwrapper"> <h4>Previous topic</h4> <p class="topless"><a href="coro.html" title="previous chapter">Coroutine Objects</a></p> <h4>Next topic</h4> <p class="topless"><a href="datetime.html" title="next chapter">DateTime Objects</a></p> <div role="note" aria-label="source link"> <h3>This Page</h3> <ul class="this-page-menu"> <li><a href="../bugs.html">Report a Bug</a></li> <li> <a href="https://github.com/python/cpython/blob/3.10/Doc/c-api/contextvars.rst" rel="nofollow">Show Source </a> </li> </ul> </div> </div> </div> <div class="clearer"></div> </div> <div class="related" role="navigation" aria-label="related navigation"> <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="datetime.html" title="DateTime Objects" >next</a> |</li> <li class="right" > <a href="coro.html" title="Coroutine Objects" >previous</a> |</li> <li><img src="../_static/py.svg" alt="python logo" style="vertical-align: middle; margin-top: -1px"/></li> <li><a href="https://www.python.org/">Python</a> »</li> <li class="switchers"> <div class="language_switcher_placeholder"></div> <div class="version_switcher_placeholder"></div> </li> <li> </li> <li id="cpython-language-and-version"> <a href="../index.html">3.10.12 Documentation</a> » </li> <li class="nav-item nav-item-1"><a href="index.html" >Python/C API Reference Manual</a> »</li> <li class="nav-item nav-item-2"><a href="concrete.html" >Concrete Objects Layer</a> »</li> <li class="nav-item nav-item-this"><a href="">Context Variables Objects</a></li> <li class="right"> <div class="inline-search" role="search"> <form class="inline-search" action="../search.html" method="get"> <input placeholder="Quick search" aria-label="Quick search" 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> </div> | </li> </ul> </div> <div class="footer"> © <a href="../copyright.html">Copyright</a> 2001-2025, Python Software Foundation. <br /> This page is licensed under the Python Software Foundation License Version 2. <br /> Examples, recipes, and other code in the documentation are additionally licensed under the Zero Clause BSD License. <br /> See <a href="/license.html">History and License</a> for more information.<br /> <br /> The Python Software Foundation is a non-profit corporation. <a href="https://www.python.org/psf/donations/">Please donate.</a> <br /> <br /> Last updated on February 04, 2025. <a href="/bugs.html">Found a bug</a>? <br /> Created using <a href="https://www.sphinx-doc.org/">Sphinx</a> 4.3.2. </div> </body> </html>