| Server IP : 121.121.20.254 / Your IP : 216.73.216.202 Web Server : Microsoft-IIS/10.0 System : Windows NT WEB-SERVER 10.0 build 20348 (Windows Server 2022) AMD64 User : IUSR ( 0) PHP Version : 8.3.28 Disable Function : NONE MySQL : ON | cURL : ON | WGET : OFF | Perl : OFF | Python : OFF | Sudo : OFF | Pkexec : OFF Directory : C:/Python315/Doc/html/extending/ |
Upload File : |
<!DOCTYPE html>
<html lang="en" data-content_root="../">
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" /><meta name="viewport" content="width=device-width, initial-scale=1" />
<meta property="og:title" content="Extending and Embedding the Python Interpreter" />
<meta property="og:type" content="website" />
<meta property="og:url" content="https://docs.python.org/3/extending/index.html" />
<meta property="og:site_name" content="Python documentation" />
<meta property="og:description" content="This document describes how to write modules in C or C++ to extend the Python interpreter with new modules. Those modules can do what Python code does – define functions, object types and methods –..." />
<meta property="og:image" content="_static/og-image.png" />
<meta property="og:image:alt" content="Python documentation" />
<meta name="description" content="This document describes how to write modules in C or C++ to extend the Python interpreter with new modules. Those modules can do what Python code does – define functions, object types and methods –..." />
<meta name="theme-color" content="#3776ab">
<meta property="og:image:width" content="200">
<meta property="og:image:height" content="200">
<title>Extending and Embedding the Python Interpreter — Python 3.15.0rc1 documentation</title><meta name="viewport" content="width=device-width, initial-scale=1.0">
<link rel="stylesheet" type="text/css" href="../_static/pygments.css?v=b86133f3" />
<link rel="stylesheet" type="text/css" href="../_static/classic.css?v=234b1a7c" />
<link rel="stylesheet" type="text/css" href="../_static/pydoctheme.css?v=4365c8fe" />
<link id="pygments_dark_css" media="(prefers-color-scheme: dark)" rel="stylesheet" type="text/css" href="../_static/pygments_dark.css?v=0fc419ee" />
<script src="../_static/documentation_options.js?v=791e38b1"></script>
<script src="../_static/doctools.js?v=9bcbadda"></script>
<script src="../_static/sphinx_highlight.js?v=dc90522c"></script>
<script src="../_static/sidebar.js"></script>
<link rel="search" type="application/opensearchdescription+xml"
title="Search within Python 3.15.0rc1 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="Your first C API extension module" href="first-extension-module.html" />
<link rel="prev" title="Security Considerations" href="../library/security_warnings.html" />
<link rel="canonical" href="https://docs.python.org/3/extending/index.html">
<style>
@media only screen {
table.full-width-table {
width: 100%;
}
}
</style>
<link rel="stylesheet" href="../_static/pydoctheme_dark.css" media="(prefers-color-scheme: dark)" id="pydoctheme_dark_css">
<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>
<script type="text/javascript" src="../_static/search-focus.js"></script>
<script type="text/javascript" src="../_static/themetoggle.js"></script>
<script type="text/javascript" src="../_static/rtd_switcher.js"></script>
<meta name="readthedocs-addons-api-version" content="1">
</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">
<nav class="nav-content" role="navigation">
<label for="menuToggler" class="toggler__label">
<span></span>
</label>
<span class="nav-items-wrapper">
<a href="https://www.python.org/" class="nav-logo">
<img src="../_static/py.svg" alt="Python logo">
</a>
<span class="version_switcher_placeholder"></span>
<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" fill="currentColor" 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"></path>
</svg>
<input placeholder="Quick search" aria-label="Quick search" type="search" name="q">
<input type="submit" value="Go">
</form>
</span>
</nav>
<div class="menu-wrapper">
<nav class="menu" role="navigation" aria-label="main navigation">
<div class="language_switcher_placeholder"></div>
<label class="theme-selector-label">
Theme
<select class="theme-selector" oninput="activateTheme(this.value)">
<option value="auto" selected>Auto</option>
<option value="light">Light</option>
<option value="dark">Dark</option>
</select>
</label>
<div>
<h3><a href="../contents.html">Table of Contents</a></h3>
<ul>
<li><a class="reference internal" href="#">Extending and Embedding the Python Interpreter</a><ul>
<li><a class="reference internal" href="#recommended-third-party-tools">Recommended third party tools</a></li>
<li><a class="reference internal" href="#c-api-tutorial">C API Tutorial</a></li>
<li><a class="reference internal" href="#guides-for-intermediate-topics">Guides for intermediate topics</a></li>
<li><a class="reference internal" href="#embedding-the-cpython-runtime-in-a-larger-application">Embedding the CPython runtime in a larger application</a></li>
</ul>
</li>
</ul>
</div>
<div>
<h4>Previous topic</h4>
<p class="topless"><a href="../library/security_warnings.html"
title="previous chapter">Security Considerations</a></p>
</div>
<div>
<h4>Next topic</h4>
<p class="topless"><a href="first-extension-module.html"
title="next chapter">Your first C API extension module</a></p>
</div>
<script>
document.addEventListener('DOMContentLoaded', () => {
const title = document.querySelector('meta[property="og:title"]').content;
const elements = document.querySelectorAll('.improvepage');
const pageurl = window.location.href.split('?')[0];
elements.forEach(element => {
const url = new URL(element.href.split('?')[0].replace("-nojs", ""));
url.searchParams.set('pagetitle', title);
url.searchParams.set('pageurl', pageurl);
url.searchParams.set('pagesource', "extending/index.rst");
element.href = url.toString();
});
});
</script>
<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 class="improvepage" href="../improve-page-nojs.html">Improve this page</a></li>
<li>
<a href="https://github.com/python/cpython/blob/main/Doc/extending/index.rst?plain=1"
rel="nofollow">Show source
</a>
</li>
</ul>
</div>
</nav>
</div>
</div>
<div class="related" role="navigation" aria-label="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="first-extension-module.html" title="Your first C API extension module"
accesskey="N">next</a> |</li>
<li class="right" >
<a href="../library/security_warnings.html" title="Security Considerations"
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">3.15.0rc1 Documentation</a> »
</li>
<li class="nav-item nav-item-this"><a href="">Extending and Embedding the Python Interpreter</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="search" name="q" id="search-box">
<input type="submit" value="Go">
</form>
</div>
|
</li>
<li class="right">
<label class="theme-selector-label">
Theme
<select class="theme-selector" oninput="activateTheme(this.value)">
<option value="auto" selected>Auto</option>
<option value="light">Light</option>
<option value="dark">Dark</option>
</select>
</label> |</li>
</ul>
</div>
<div class="document">
<div class="documentwrapper">
<div class="bodywrapper">
<div class="body" role="main">
<section id="extending-and-embedding-the-python-interpreter">
<span id="extending-index"></span><h1>Extending and Embedding the Python Interpreter<a class="headerlink" href="#extending-and-embedding-the-python-interpreter" title="Link to this heading">¶</a></h1>
<p>This document describes how to write modules in C or C++ to extend the Python
interpreter with new modules. Those modules can do what Python code does –
define functions, object types and methods – but also interact with native
libraries or achieve better performance by avoiding the overhead of an
interpreter. The document also describes how
to embed the Python interpreter in another application, for use as an extension
language. Finally, it shows how to compile and link extension modules so that
they can be loaded dynamically (at run time) into the interpreter, if the
underlying operating system supports this feature.</p>
<p>This document assumes basic knowledge about C and Python. For an informal
introduction to Python, see <a class="reference internal" href="../tutorial/index.html#tutorial-index"><span class="std std-ref">The Python Tutorial</span></a>. <a class="reference internal" href="../reference/index.html#reference-index"><span class="std std-ref">The Python Language Reference</span></a>
gives a more formal definition of the language. <a class="reference internal" href="../library/index.html#library-index"><span class="std std-ref">The Python Standard Library</span></a> documents
the existing object types, functions and modules (both built-in and written in
Python) that give the language its wide application range.</p>
<p>For a detailed description of the whole Python/C API, see the separate
<a class="reference internal" href="../c-api/index.html#c-api-index"><span class="std std-ref">Python/C API reference manual</span></a>.</p>
<p>To support extensions, Python’s C API (Application Programmers Interface)
defines a set of functions, macros and variables that provide access to most
aspects of the Python run-time system. The Python API is incorporated in a C
source file by including the header <code class="docutils literal notranslate"><span class="pre">"Python.h"</span></code>.</p>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>The C extension interface is specific to CPython, and extension modules do
not work on other Python implementations. In many cases, it is possible to
avoid writing C extensions and preserve portability to other implementations.
For example, if your use case is calling C library functions or system calls,
you should consider using the <a class="reference internal" href="../library/ctypes.html#module-ctypes" title="ctypes: A foreign function library for Python."><code class="xref py py-mod docutils literal notranslate"><span class="pre">ctypes</span></code></a> module or the <a class="reference external" href="https://cffi.readthedocs.io/">cffi</a> library rather than writing
custom C code.
These modules let you write Python code to interface with C code and are more
portable between implementations of Python than writing and compiling a C
extension module.</p>
</div>
<div class="toctree-wrapper compound">
</div>
<section id="recommended-third-party-tools">
<h2>Recommended third party tools<a class="headerlink" href="#recommended-third-party-tools" title="Link to this heading">¶</a></h2>
<p>This document only covers the basic tools for creating extensions provided
as part of this version of CPython. Some <a class="reference internal" href="../c-api/intro.html#c-api-tools"><span class="std std-ref">third party tools</span></a> offer both simpler and more sophisticated approaches to creating
C and C++ extensions for Python.</p>
<p>While this document is aimed at extension authors, it should also be helpful to
the authors of such tools.
For example, the tutorial module can serve as a simple test case for a build
tool or sample expected output of a code generator.</p>
</section>
<section id="c-api-tutorial">
<h2>C API Tutorial<a class="headerlink" href="#c-api-tutorial" title="Link to this heading">¶</a></h2>
<p>This tutorial describes how to write a simple module in C or C++,
using the Python C API – that is, using the basic tools provided
as part of this version of CPython.</p>
<ol class="arabic simple">
<li><p><a class="reference internal" href="first-extension-module.html#first-extension-module"><span class="std std-ref">Your first C API extension module</span></a></p></li>
</ol>
</section>
<section id="guides-for-intermediate-topics">
<h2>Guides for intermediate topics<a class="headerlink" href="#guides-for-intermediate-topics" title="Link to this heading">¶</a></h2>
<p>This section of the guide covers creating C and C++ extensions without
assistance from third party tools. It is intended primarily for creators
of those tools, rather than being a recommended way to create your own
C extensions.</p>
<ul class="simple">
<li><p><a class="reference internal" href="extending.html#extending-intro"><span class="std std-ref">Using the C API: Assorted topics</span></a></p></li>
<li><p><a class="reference internal" href="newtypes_tutorial.html#defining-new-types"><span class="std std-ref">Defining Extension Types: Tutorial</span></a></p></li>
<li><p><a class="reference internal" href="newtypes.html#new-types-topics"><span class="std std-ref">Defining Extension Types: Assorted Topics</span></a></p></li>
<li><p><a class="reference internal" href="building.html#building"><span class="std std-ref">Building C and C++ Extensions</span></a></p></li>
<li><p><a class="reference internal" href="windows.html#building-on-windows"><span class="std std-ref">Building C and C++ Extensions on Windows</span></a></p></li>
</ul>
</section>
<section id="embedding-the-cpython-runtime-in-a-larger-application">
<h2>Embedding the CPython runtime in a larger application<a class="headerlink" href="#embedding-the-cpython-runtime-in-a-larger-application" title="Link to this heading">¶</a></h2>
<p>Sometimes, rather than creating an extension that runs inside the Python
interpreter as the main application, it is desirable to instead embed
the CPython runtime inside a larger application. This section covers
some of the details involved in doing that successfully.</p>
<ul class="simple">
<li><p><a class="reference internal" href="embedding.html#embedding"><span class="std std-ref">Embedding Python in Another Application</span></a></p></li>
</ul>
</section>
</section>
<div class="clearer"></div>
</div>
</div>
</div>
<div class="sphinxsidebar" role="navigation" aria-label="Main">
<div class="sphinxsidebarwrapper">
<div>
<h3><a href="../contents.html">Table of Contents</a></h3>
<ul>
<li><a class="reference internal" href="#">Extending and Embedding the Python Interpreter</a><ul>
<li><a class="reference internal" href="#recommended-third-party-tools">Recommended third party tools</a></li>
<li><a class="reference internal" href="#c-api-tutorial">C API Tutorial</a></li>
<li><a class="reference internal" href="#guides-for-intermediate-topics">Guides for intermediate topics</a></li>
<li><a class="reference internal" href="#embedding-the-cpython-runtime-in-a-larger-application">Embedding the CPython runtime in a larger application</a></li>
</ul>
</li>
</ul>
</div>
<div>
<h4>Previous topic</h4>
<p class="topless"><a href="../library/security_warnings.html"
title="previous chapter">Security Considerations</a></p>
</div>
<div>
<h4>Next topic</h4>
<p class="topless"><a href="first-extension-module.html"
title="next chapter">Your first C API extension module</a></p>
</div>
<script>
document.addEventListener('DOMContentLoaded', () => {
const title = document.querySelector('meta[property="og:title"]').content;
const elements = document.querySelectorAll('.improvepage');
const pageurl = window.location.href.split('?')[0];
elements.forEach(element => {
const url = new URL(element.href.split('?')[0].replace("-nojs", ""));
url.searchParams.set('pagetitle', title);
url.searchParams.set('pageurl', pageurl);
url.searchParams.set('pagesource', "extending/index.rst");
element.href = url.toString();
});
});
</script>
<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 class="improvepage" href="../improve-page-nojs.html">Improve this page</a></li>
<li>
<a href="https://github.com/python/cpython/blob/main/Doc/extending/index.rst?plain=1"
rel="nofollow">Show source
</a>
</li>
</ul>
</div>
</div>
<div id="sidebarbutton" title="Collapse sidebar">
<span>«</span>
</div>
</div>
<div class="clearer"></div>
</div>
<div class="related" role="navigation" aria-label="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="first-extension-module.html" title="Your first C API extension module"
>next</a> |</li>
<li class="right" >
<a href="../library/security_warnings.html" title="Security Considerations"
>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">3.15.0rc1 Documentation</a> »
</li>
<li class="nav-item nav-item-this"><a href="">Extending and Embedding the Python Interpreter</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="search" name="q" id="search-box">
<input type="submit" value="Go">
</form>
</div>
|
</li>
<li class="right">
<label class="theme-selector-label">
Theme
<select class="theme-selector" oninput="activateTheme(this.value)">
<option value="auto" selected>Auto</option>
<option value="light">Light</option>
<option value="dark">Dark</option>
</select>
</label> |</li>
</ul>
</div>
<div class="footer">
© <a href="../copyright.html">Copyright</a> 2001 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 Aug 04, 2026 (11:13 UTC).
<a href="/bugs.html">Found a bug</a>?
<br>
Created using <a href="https://www.sphinx-doc.org/">Sphinx</a> 8.2.3.
</div>
</body>
</html>