<!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="API and ABI Versioning" />
<meta property="og:type" content="website" />
<meta property="og:url" content="https://docs.python.org/3/c-api/apiabiversion.html" />
<meta property="og:site_name" content="Python documentation" />
<meta property="og:description" content="CPython exposes its version number in the following macros. Note that these correspond to the version code is built with, not necessarily the version used at run time. See C API Stability for a dis..." />
<meta property="og:image" content="https://docs.python.org/3/_static/og-image.png" />
<meta property="og:image:alt" content="Python documentation" />
<meta name="description" content="CPython exposes its version number in the following macros. Note that these correspond to the version code is built with, not necessarily the version used at run time. See C API Stability for a dis..." />
<meta property="og:image:width" content="200">
<meta property="og:image:height" content="200">
<meta name="theme-color" content="#3776ab">
<title>API and ABI Versioning — Python 3.13.3 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/pydoctheme.css?v=23252803" />
<link id="pygments_dark_css" media="(prefers-color-scheme: dark)" rel="stylesheet" type="text/css" href="../_static/pygments_dark.css?v=5349f25f" />
<script src="../_static/documentation_options.js?v=5d57ca2d"></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 3.13.3 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="Monitoring C API" href="monitoring.html" />
<link rel="prev" title="Supporting Cyclic Garbage Collection" href="gcsupport.html" />
<link rel="canonical" href="https://docs.python.org/3/c-api/apiabiversion.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>
<h4>Previous topic</h4>
<p class="topless"><a href="gcsupport.html"
title="previous chapter">Supporting Cyclic Garbage Collection</a></p>
</div>
<div>
<h4>Next topic</h4>
<p class="topless"><a href="monitoring.html"
title="next chapter">Monitoring C API</a></p>
</div>
<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/main/Doc/c-api/apiabiversion.rst"
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="monitoring.html" title="Monitoring C API"
accesskey="N">next</a> |</li>
<li class="right" >
<a href="gcsupport.html" title="Supporting Cyclic Garbage Collection"
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">3.13.3 Documentation</a> »
</li>
<li class="nav-item nav-item-1"><a href="index.html" accesskey="U">Python/C API Reference Manual</a> »</li>
<li class="nav-item nav-item-this"><a href="">API and ABI Versioning</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="api-and-abi-versioning">
<span id="apiabiversion"></span><h1>API and ABI Versioning<a class="headerlink" href="#api-and-abi-versioning" title="Link to this heading">¶</a></h1>
<p>CPython exposes its version number in the following macros.
Note that these correspond to the version code is <strong>built</strong> with,
not necessarily the version used at <strong>run time</strong>.</p>
<p>See <a class="reference internal" href="stable.html#stable"><span class="std std-ref">C API Stability</span></a> for a discussion of API and ABI stability across versions.</p>
<dl class="c macro">
<dt class="sig sig-object c" id="c.PY_MAJOR_VERSION">
<span class="sig-name descname"><span class="n"><span class="pre">PY_MAJOR_VERSION</span></span></span><a class="headerlink" href="#c.PY_MAJOR_VERSION" title="Link to this definition">¶</a><br /></dt>
<dd><p>The <code class="docutils literal notranslate"><span class="pre">3</span></code> in <code class="docutils literal notranslate"><span class="pre">3.4.1a2</span></code>.</p>
</dd></dl>
<dl class="c macro">
<dt class="sig sig-object c" id="c.PY_MINOR_VERSION">
<span class="sig-name descname"><span class="n"><span class="pre">PY_MINOR_VERSION</span></span></span><a class="headerlink" href="#c.PY_MINOR_VERSION" title="Link to this definition">¶</a><br /></dt>
<dd><p>The <code class="docutils literal notranslate"><span class="pre">4</span></code> in <code class="docutils literal notranslate"><span class="pre">3.4.1a2</span></code>.</p>
</dd></dl>
<dl class="c macro">
<dt class="sig sig-object c" id="c.PY_MICRO_VERSION">
<span class="sig-name descname"><span class="n"><span class="pre">PY_MICRO_VERSION</span></span></span><a class="headerlink" href="#c.PY_MICRO_VERSION" title="Link to this definition">¶</a><br /></dt>
<dd><p>The <code class="docutils literal notranslate"><span class="pre">1</span></code> in <code class="docutils literal notranslate"><span class="pre">3.4.1a2</span></code>.</p>
</dd></dl>
<dl class="c macro">
<dt class="sig sig-object c" id="c.PY_RELEASE_LEVEL">
<span class="sig-name descname"><span class="n"><span class="pre">PY_RELEASE_LEVEL</span></span></span><a class="headerlink" href="#c.PY_RELEASE_LEVEL" title="Link to this definition">¶</a><br /></dt>
<dd><p>The <code class="docutils literal notranslate"><span class="pre">a</span></code> in <code class="docutils literal notranslate"><span class="pre">3.4.1a2</span></code>.
This can be <code class="docutils literal notranslate"><span class="pre">0xA</span></code> for alpha, <code class="docutils literal notranslate"><span class="pre">0xB</span></code> for beta, <code class="docutils literal notranslate"><span class="pre">0xC</span></code> for release
candidate or <code class="docutils literal notranslate"><span class="pre">0xF</span></code> for final.</p>
</dd></dl>
<dl class="c macro">
<dt class="sig sig-object c" id="c.PY_RELEASE_SERIAL">
<span class="sig-name descname"><span class="n"><span class="pre">PY_RELEASE_SERIAL</span></span></span><a class="headerlink" href="#c.PY_RELEASE_SERIAL" title="Link to this definition">¶</a><br /></dt>
<dd><p>The <code class="docutils literal notranslate"><span class="pre">2</span></code> in <code class="docutils literal notranslate"><span class="pre">3.4.1a2</span></code>. Zero for final releases.</p>
</dd></dl>
<dl class="c macro">
<dt class="sig sig-object c" id="c.PY_VERSION_HEX">
<span class="sig-name descname"><span class="n"><span class="pre">PY_VERSION_HEX</span></span></span><a class="headerlink" href="#c.PY_VERSION_HEX" title="Link to this definition">¶</a><br /></dt>
<dd><p>The Python version number encoded in a single integer.</p>
<p>The underlying version information can be found by treating it as a 32 bit
number in the following manner:</p>
<table class="docutils align-default">
<thead>
<tr class="row-odd"><th class="head"><p>Bytes</p></th>
<th class="head"><p>Bits (big endian order)</p></th>
<th class="head"><p>Meaning</p></th>
<th class="head"><p>Value for <code class="docutils literal notranslate"><span class="pre">3.4.1a2</span></code></p></th>
</tr>
</thead>
<tbody>
<tr class="row-even"><td><p>1</p></td>
<td><p>1-8</p></td>
<td><p><code class="docutils literal notranslate"><span class="pre">PY_MAJOR_VERSION</span></code></p></td>
<td><p><code class="docutils literal notranslate"><span class="pre">0x03</span></code></p></td>
</tr>
<tr class="row-odd"><td><p>2</p></td>
<td><p>9-16</p></td>
<td><p><code class="docutils literal notranslate"><span class="pre">PY_MINOR_VERSION</span></code></p></td>
<td><p><code class="docutils literal notranslate"><span class="pre">0x04</span></code></p></td>
</tr>
<tr class="row-even"><td><p>3</p></td>
<td><p>17-24</p></td>
<td><p><code class="docutils literal notranslate"><span class="pre">PY_MICRO_VERSION</span></code></p></td>
<td><p><code class="docutils literal notranslate"><span class="pre">0x01</span></code></p></td>
</tr>
<tr class="row-odd"><td rowspan="2"><p>4</p></td>
<td><p>25-28</p></td>
<td><p><code class="docutils literal notranslate"><span class="pre">PY_RELEASE_LEVEL</span></code></p></td>
<td><p><code class="docutils literal notranslate"><span class="pre">0xA</span></code></p></td>
</tr>
<tr class="row-even"><td><p>29-32</p></td>
<td><p><code class="docutils literal notranslate"><span class="pre">PY_RELEASE_SERIAL</span></code></p></td>
<td><p><code class="docutils literal notranslate"><span class="pre">0x2</span></code></p></td>
</tr>
</tbody>
</table>
<p>Thus <code class="docutils literal notranslate"><span class="pre">3.4.1a2</span></code> is hexversion <code class="docutils literal notranslate"><span class="pre">0x030401a2</span></code> and <code class="docutils literal notranslate"><span class="pre">3.10.0</span></code> is
hexversion <code class="docutils literal notranslate"><span class="pre">0x030a00f0</span></code>.</p>
<p>Use this for numeric comparisons, e.g. <code class="docutils literal notranslate"><span class="pre">#if</span> <span class="pre">PY_VERSION_HEX</span> <span class="pre">>=</span> <span class="pre">...</span></code>.</p>
<p>This version is also available via the symbol <a class="reference internal" href="#c.Py_Version" title="Py_Version"><code class="xref c c-var docutils literal notranslate"><span class="pre">Py_Version</span></code></a>.</p>
</dd></dl>
<dl class="c var">
<dt class="sig sig-object c" id="c.Py_Version">
<span class="k"><span class="pre">const</span></span><span class="w"> </span><span class="kt"><span class="pre">unsigned</span></span><span class="w"> </span><span class="kt"><span class="pre">long</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">Py_Version</span></span></span><a class="headerlink" href="#c.Py_Version" title="Link to this definition">¶</a><br /></dt>
<dd><em class="stableabi"> Part of the <a class="reference internal" href="stable.html#stable"><span class="std std-ref">Stable ABI</span></a> since version 3.11.</em><p>The Python runtime version number encoded in a single constant integer, with
the same format as the <a class="reference internal" href="#c.PY_VERSION_HEX" title="PY_VERSION_HEX"><code class="xref c c-macro docutils literal notranslate"><span class="pre">PY_VERSION_HEX</span></code></a> macro.
This contains the Python version used at run time.</p>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.11.</span></p>
</div>
</dd></dl>
<p>All the given macros are defined in <a class="extlink-source reference external" href="https://github.com/python/cpython/tree/3.13/Include/patchlevel.h">Include/patchlevel.h</a>.</p>
</section>
<div class="clearer"></div>
</div>
</div>
</div>
<div class="sphinxsidebar" role="navigation" aria-label="Main">
<div class="sphinxsidebarwrapper">
<div>
<h4>Previous topic</h4>
<p class="topless"><a href="gcsupport.html"
title="previous chapter">Supporting Cyclic Garbage Collection</a></p>
</div>
<div>
<h4>Next topic</h4>
<p class="topless"><a href="monitoring.html"
title="next chapter">Monitoring C API</a></p>
</div>
<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/main/Doc/c-api/apiabiversion.rst"
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="monitoring.html" title="Monitoring C API"
>next</a> |</li>
<li class="right" >
<a href="gcsupport.html" title="Supporting Cyclic Garbage Collection"
>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">3.13.3 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-this"><a href="">API and ABI Versioning</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>
2001-2025, 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 Apr 08, 2025 (14:33 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>