<!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta charset="utf-8" /> <title>API and ABI Versioning — Python 3.7.4 documentation</title> <link rel="stylesheet" href="../_static/pydoctheme.css" type="text/css" /> <link rel="stylesheet" href="../_static/pygments.css" type="text/css" /> <script type="text/javascript" id="documentation_options" data-url_root="../" src="../_static/documentation_options.js"></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/language_data.js"></script> <script type="text/javascript" src="../_static/sidebar.js"></script> <link rel="search" type="application/opensearchdescription+xml" title="Search within Python 3.7.4 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="Distributing Python Modules" href="../distributing/index.html" /> <link rel="prev" title="Supporting Cyclic Garbage Collection" href="gcsupport.html" /> <link rel="shortcut icon" type="image/png" href="../_static/py.png" /> <link rel="canonical" href="https://docs.python.org/3/c-api/apiabiversion.html" /> <script type="text/javascript" src="../_static/copybutton.js"></script> <script type="text/javascript" src="../_static/switchers.js"></script> <style> @media only screen { table.full-width-table { width: 100%; } } </style> </head><body> <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="../distributing/index.html" title="Distributing Python Modules" 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.png" alt="" style="vertical-align: middle; margin-top: -1px"/></li> <li><a href="https://www.python.org/">Python</a> »</li> <li> <span class="language_switcher_placeholder">en</span> <span class="version_switcher_placeholder">3.7.4</span> <a href="../index.html">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="right"> <div class="inline-search" style="display: none" role="search"> <form class="inline-search" action="../search.html" method="get"> <input placeholder="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> <script type="text/javascript">$('.inline-search').show(0);</script> | </li> </ul> </div> <div class="document"> <div class="documentwrapper"> <div class="bodywrapper"> <div class="body" role="main"> <div class="section" id="api-and-abi-versioning"> <span id="apiabiversion"></span><h1>API and ABI Versioning<a class="headerlink" href="#api-and-abi-versioning" title="Permalink to this headline">ΒΆ</a></h1> <p><code class="docutils literal notranslate"><span class="pre">PY_VERSION_HEX</span></code> is the Python version number encoded in a single integer.</p> <p>For example if the <code class="docutils literal notranslate"><span class="pre">PY_VERSION_HEX</span></code> is set to <code class="docutils literal notranslate"><span class="pre">0x030401a2</span></code>, the underlying version information can be found by treating it as a 32 bit number in the following manner:</p> <blockquote> <div><table class="docutils align-center"> <colgroup> <col style="width: 9%" /> <col style="width: 31%" /> <col style="width: 60%" /> </colgroup> <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> </tr> </thead> <tbody> <tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">1</span></code></p></td> <td><p><code class="docutils literal notranslate"><span class="pre">1-8</span></code></p></td> <td><p><code class="docutils literal notranslate"><span class="pre">PY_MAJOR_VERSION</span></code> (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></td> </tr> <tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">2</span></code></p></td> <td><p><code class="docutils literal notranslate"><span class="pre">9-16</span></code></p></td> <td><p><code class="docutils literal notranslate"><span class="pre">PY_MINOR_VERSION</span></code> (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></td> </tr> <tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">3</span></code></p></td> <td><p><code class="docutils literal notranslate"><span class="pre">17-24</span></code></p></td> <td><p><code class="docutils literal notranslate"><span class="pre">PY_MICRO_VERSION</span></code> (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></td> </tr> <tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">4</span></code></p></td> <td><p><code class="docutils literal notranslate"><span class="pre">25-28</span></code></p></td> <td><p><code class="docutils literal notranslate"><span class="pre">PY_RELEASE_LEVEL</span></code> (<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 and <code class="docutils literal notranslate"><span class="pre">0xF</span></code> for final), in this case it is alpha.</p></td> </tr> <tr class="row-even"><td></td> <td><p><code class="docutils literal notranslate"><span class="pre">29-32</span></code></p></td> <td><p><code class="docutils literal notranslate"><span class="pre">PY_RELEASE_SERIAL</span></code> (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></td> </tr> </tbody> </table> </div></blockquote> <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>.</p> <p>All the given macros are defined in <a class="reference external" href="https://github.com/python/cpython/tree/3.7/Include/patchlevel.h">Include/patchlevel.h</a>.</p> </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="gcsupport.html" title="previous chapter">Supporting Cyclic Garbage Collection</a></p> <h4>Next topic</h4> <p class="topless"><a href="../distributing/index.html" title="next chapter">Distributing Python Modules</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/3.7/Doc/c-api/apiabiversion.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="../distributing/index.html" title="Distributing Python Modules" >next</a> |</li> <li class="right" > <a href="gcsupport.html" title="Supporting Cyclic Garbage Collection" >previous</a> |</li> <li><img src="../_static/py.png" alt="" style="vertical-align: middle; margin-top: -1px"/></li> <li><a href="https://www.python.org/">Python</a> »</li> <li> <span class="language_switcher_placeholder">en</span> <span class="version_switcher_placeholder">3.7.4</span> <a href="../index.html">Documentation </a> » </li> <li class="nav-item nav-item-1"><a href="index.html" >Python/C API Reference Manual</a> »</li> <li class="right"> <div class="inline-search" style="display: none" role="search"> <form class="inline-search" action="../search.html" method="get"> <input placeholder="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> <script type="text/javascript">$('.inline-search').show(0);</script> | </li> </ul> </div> <div class="footer"> © <a href="../copyright.html">Copyright</a> 2001-2019, Python Software Foundation. <br /> The Python Software Foundation is a non-profit corporation. <a href="https://www.python.org/psf/donations/">Please donate.</a> <br /> Last updated on Jul 13, 2019. <a href="../bugs.html">Found a bug</a>? <br /> Created using <a href="http://sphinx.pocoo.org/">Sphinx</a> 2.0.1. </div> </body> </html>