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<!DOCTYPE html> <html class="writer-html4" lang="en" > <head> <meta charset="utf-8" /> <meta name="viewport" content="width=device-width, initial-scale=1.0" /> <title>Welcome to PyPy鈥檚 documentation! — PyPy documentation</title><link rel="stylesheet" href="_static/css/theme.css" type="text/css" /> <link rel="stylesheet" href="_static/pygments.css" type="text/css" /> <link rel="stylesheet" href="_static/graphviz.css" type="text/css" /> <link rel="canonical" href="https://doc.pypy.org/en/latest/index.html" />  <script 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 src="_static/js/theme.js"></script> <link rel="index" title="Index" href="genindex.html" /> <link 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id="welcome-to-pypy-s-documentation"> <h1>Welcome to PyPy鈥檚 documentation!<a class="headerlink" href="#welcome-to-pypy-s-documentation" title="Permalink to this headline">露</a></h1> <p>Welcome to the documentation for PyPy, a <a class="reference external" href="https://speed.pypy.org">fast</a>, compliant alternative implementation of the <a class="reference external" href="https://python.org/">Python</a> language.</p> <ul class="simple"> <li>If you want to find out more about what PyPy is, have a look at our <a class="reference internal" href="introduction.html"><span class="doc">What is PyPy?</span></a> or consult the <a class="reference external" href="https://pypy.org/">PyPy website</a>.</li> <li>If you鈥檙e interested in trying PyPy out, check out the <a class="reference internal" href="install.html"><span class="doc">installation instructions</span></a>.</li> <li>If you want to help develop PyPy, please have a look at <a class="reference internal" href="contributing.html"><span class="doc">contributing</span></a> and at the repo on <a class="reference external" href="https://github.com/pypy/pypy">https://github.com/pypy/pypy</a> and get in touch (<a class="reference internal" href="#contact"><span class="std std-ref">Contact</span></a>)!</li> </ul> <p>All of the documentation and source code is available under the MIT license, unless otherwise specified. Consult <a class="reference external" href="https://github.com/pypy/pypy/blob/main/LICENSE">LICENSE</a>.</p> <div class="section" id="getting-started"> <span id="getting-started-index"></span><h2>Getting Started<a class="headerlink" href="#getting-started" title="Permalink to this headline">露</a></h2> <div class="toctree-wrapper compound"> <ul> <li class="toctree-l1"><a class="reference internal" href="introduction.html">What is PyPy?</a></li> <li class="toctree-l1"><a class="reference internal" href="architecture.html">Goals and Architecture Overview</a></li> <li class="toctree-l1"><a class="reference internal" href="install.html">Downloading and Installing PyPy</a></li> <li class="toctree-l1"><a class="reference internal" href="build.html">Building PyPy from Source</a></li> <li class="toctree-l1"><a class="reference internal" href="windows.html">Translating on Windows</a></li> <li class="toctree-l1"><a class="reference internal" href="faq.html">Frequently Asked Questions</a></li> </ul> </div> </div> <div class="section" id="using-pypy"> <span id="id1"></span><h2>Using PyPy<a class="headerlink" href="#using-pypy" title="Permalink to this headline">露</a></h2> <div class="toctree-wrapper compound"> <ul> <li class="toctree-l1"><a class="reference internal" href="cpython_differences.html">Differences between PyPy and CPython</a><ul> <li class="toctree-l2"><a class="reference internal" href="cpython_differences.html#differences-related-to-garbage-collection-strategies">Differences related to garbage collection strategies</a></li> <li class="toctree-l2"><a class="reference internal" href="cpython_differences.html#missing-sys-getrefcount">Missing <code class="docutils literal notranslate"><span class="pre">sys.getrefcount</span></code></a></li> <li class="toctree-l2"><a class="reference internal" href="cpython_differences.html#subclasses-of-built-in-types">Subclasses of built-in types</a></li> <li class="toctree-l2"><a class="reference internal" href="cpython_differences.html#mutating-classes-of-objects-which-are-already-used-as-dictionary-keys">Mutating classes of objects which are already used as dictionary keys</a></li> <li class="toctree-l2"><a class="reference internal" href="cpython_differences.html#ignored-exceptions">Ignored exceptions</a></li> <li class="toctree-l2"><a class="reference internal" href="cpython_differences.html#object-identity-of-primitive-values-is-and-id">Object Identity of Primitive Values, <code class="docutils literal notranslate"><span class="pre">is</span></code> and <code class="docutils literal notranslate"><span class="pre">id</span></code></a></li> <li class="toctree-l2"><a class="reference internal" href="cpython_differences.html#permitted-abi-tags-in-extensions">Permitted ABI tags in extensions</a></li> <li class="toctree-l2"><a class="reference internal" href="cpython_differences.html#c-api-differences">C-API Differences</a></li> <li class="toctree-l2"><a class="reference internal" href="cpython_differences.html#performance-differences">Performance Differences</a></li> <li class="toctree-l2"><a class="reference internal" href="cpython_differences.html#miscellaneous">Miscellaneous</a></li> <li class="toctree-l2"><a class="reference internal" href="cpython_differences.html#extension-modules">Extension modules</a></li> </ul> </li> <li class="toctree-l1"><a class="reference internal" href="extending.html">Writing extension modules for pypy</a><ul> <li class="toctree-l2"><a class="reference internal" href="extending.html#cffi">CFFI</a></li> <li class="toctree-l2"><a class="reference internal" href="extending.html#ctypes">CTypes</a></li> <li class="toctree-l2"><a class="reference internal" href="extending.html#cppyy">cppyy</a></li> <li class="toctree-l2"><a class="reference internal" href="extending.html#rpython-mixed-modules">RPython Mixed Modules</a></li> </ul> </li> <li class="toctree-l1"><a class="reference internal" href="gc_info.html">Garbage collector documentation and configuration</a><ul> <li class="toctree-l2"><a class="reference internal" href="gc_info.html#incminimark">Incminimark</a></li> <li class="toctree-l2"><a class="reference internal" href="gc_info.html#semi-manual-gc-management">Semi-manual GC management</a></li> <li class="toctree-l2"><a class="reference internal" href="gc_info.html#fragmentation">Fragmentation</a></li> <li class="toctree-l2"><a class="reference internal" href="gc_info.html#gc-get-stats">gc.get_stats</a></li> <li class="toctree-l2"><a class="reference internal" href="gc_info.html#gc-hooks">GC Hooks</a></li> <li class="toctree-l2"><a class="reference internal" href="gc_info.html#environment-variables">Environment variables</a></li> </ul> </li> <li class="toctree-l1"><a class="reference internal" href="jit-hooks.html">JIT hooks</a></li> <li class="toctree-l1"><a class="reference internal" href="jit-hooks.html#resetting-the-jit">Resetting the JIT</a></li> <li class="toctree-l1"><a class="reference internal" href="stackless.html">Application-level Stackless features</a><ul> <li class="toctree-l2"><a class="reference internal" href="stackless.html#introduction">Introduction</a></li> <li class="toctree-l2"><a class="reference internal" href="stackless.html#theory">Theory</a></li> <li class="toctree-l2"><a class="reference internal" href="stackless.html#application-level-interface">Application level interface</a></li> </ul> </li> <li class="toctree-l1"><a class="reference internal" href="__pypy__-module.html">The <code class="docutils literal notranslate"><span class="pre">__pypy__</span></code> module</a><ul> <li class="toctree-l2"><a class="reference internal" href="__pypy__-module.html#generally-available-functionality">Generally available functionality</a></li> <li class="toctree-l2"><a class="reference internal" href="__pypy__-module.html#fast-string-concatenation">Fast String Concatenation</a></li> <li class="toctree-l2"><a class="reference internal" href="__pypy__-module.html#interacting-with-the-pypy-debug-log">Interacting with the PyPy debug log</a></li> <li class="toctree-l2"><a class="reference internal" href="__pypy__-module.html#transparent-proxy-functionality">Transparent Proxy Functionality</a></li> <li class="toctree-l2"><a class="reference internal" href="__pypy__-module.html#additional-clocks-for-timing">Additional Clocks for Timing</a></li> <li class="toctree-l2"><a class="reference internal" href="__pypy__-module.html#extended-signal-handling">Extended Signal Handling</a></li> <li class="toctree-l2"><a class="reference internal" href="__pypy__-module.html#integer-operations-with-overflow">Integer Operations with Overflow</a></li> <li class="toctree-l2"><a class="reference internal" href="__pypy__-module.html#functionality-available-on-py-py-not-after-translation">Functionality available on py.py (not after translation)</a></li> </ul> </li> <li class="toctree-l1"><a class="reference internal" href="sandbox.html">PyPy鈥檚 sandboxing features</a><ul> <li class="toctree-l2"><a class="reference internal" href="sandbox.html#introduction">Introduction</a></li> <li class="toctree-l2"><a class="reference internal" href="sandbox.html#overview">Overview</a></li> <li class="toctree-l2"><a class="reference internal" href="sandbox.html#howto">Howto</a></li> </ul> </li> <li class="toctree-l1"><a class="reference internal" href="stm.html">Software Transactional Memory</a><ul> <li class="toctree-l2"><a class="reference internal" href="stm.html#what-pypy-stm-is-for">What pypy-stm is for</a></li> <li class="toctree-l2"><a class="reference internal" href="stm.html#getting-started">Getting Started</a></li> <li class="toctree-l2"><a class="reference internal" href="stm.html#python-3-cpython-and-others">Python 3, CPython, and others</a></li> <li class="toctree-l2"><a class="reference internal" href="stm.html#user-guide">User Guide</a></li> <li class="toctree-l2"><a class="reference internal" href="stm.html#implementation">Implementation</a></li> <li class="toctree-l2"><a class="reference internal" href="stm.html#see-also">See also</a></li> </ul> </li> <li class="toctree-l1"><a class="reference internal" href="remotedebugging.html">Remote Debugging</a><ul> <li class="toctree-l2"><a class="reference internal" href="remotedebugging.html#from-the-commandline">From the commandline</a></li> <li class="toctree-l2"><a class="reference internal" href="remotedebugging.html#api">API</a></li> <li class="toctree-l2"><a class="reference internal" href="remotedebugging.html#security">Security</a></li> </ul> </li> </ul> </div> </div> <div class="section" id="development"> <h2>Development<a class="headerlink" href="#development" title="Permalink to this headline">露</a></h2> <div class="toctree-wrapper compound"> <ul> <li class="toctree-l1"><a class="reference internal" href="contributing.html">Contributing Guidelines</a><ul> <li class="toctree-l2"><a class="reference internal" href="contributing.html#getting-involved">Getting involved</a></li> <li class="toctree-l2"><a class="reference internal" href="contributing.html#your-first-contribution">Your first contribution</a></li> <li class="toctree-l2"><a class="reference internal" href="contributing.html#architecture">Architecture</a></li> <li class="toctree-l2"><a class="reference internal" href="contributing.html#building">Building</a></li> <li class="toctree-l2"><a class="reference internal" href="contributing.html#testing">Testing</a></li> <li class="toctree-l2"><a class="reference internal" href="contributing.html#tooling-utilities">Tooling & Utilities</a></li> <li class="toctree-l2"><a class="reference internal" href="contributing.html#demos">Demos</a></li> <li class="toctree-l2"><a class="reference internal" href="contributing.html#graphviz-pygame-for-flow-graph-viewing-highly-recommended">graphviz & pygame for flow graph viewing (highly recommended)</a></li> </ul> </li> <li class="toctree-l1"><a class="reference internal" href="configuration.html">PyPy鈥檚 Configuration Handling</a><ul> <li class="toctree-l2"><a class="reference internal" href="configuration.html#main-assumption">Main Assumption</a></li> <li class="toctree-l2"><a class="reference internal" href="configuration.html#api-details">API Details</a></li> <li class="toctree-l2"><a class="reference internal" href="configuration.html#the-usage-of-config-objects-in-pypy">The usage of config objects in PyPy</a></li> </ul> </li> <li class="toctree-l1"><a class="reference internal" href="project-ideas.html">Potential Project List</a><ul> <li class="toctree-l2"><a class="reference internal" href="project-ideas.html#getting-involved">Getting involved</a></li> <li class="toctree-l2"><a class="reference internal" href="project-ideas.html#simple-tasks-for-newcomers">Simple tasks for newcomers</a></li> <li class="toctree-l2"><a class="reference internal" href="project-ideas.html#mid-to-large-tasks">Mid-to-large tasks</a></li> <li class="toctree-l2"><a class="reference internal" href="project-ideas.html#explicit-typing-in-rpython">Explicit typing in RPython</a></li> <li class="toctree-l2"><a class="reference internal" href="project-ideas.html#make-bytearray-type-fast">Make bytearray type fast</a></li> <li class="toctree-l2"><a class="reference internal" href="project-ideas.html#implement-copy-on-write-list-slicing">Implement copy-on-write list slicing</a></li> <li class="toctree-l2"><a class="reference internal" href="project-ideas.html#numpy-rebooted">NumPy rebooted</a></li> <li class="toctree-l2"><a class="reference internal" href="project-ideas.html#improving-the-jitviewer">Improving the jitviewer</a></li> <li class="toctree-l2"><a class="reference internal" href="project-ideas.html#convert-rpython-to-python3">Convert RPython to Python3</a></li> <li class="toctree-l2"><a class="reference internal" href="project-ideas.html#improve-performance">Improve performance</a></li> <li class="toctree-l2"><a class="reference internal" href="project-ideas.html#improve-warmup">Improve warmup</a></li> <li class="toctree-l2"><a class="reference internal" href="project-ideas.html#translation-toolchain">Translation Toolchain</a></li> <li class="toctree-l2"><a class="reference internal" href="project-ideas.html#various-gcs">Various GCs</a></li> <li class="toctree-l2"><a class="reference internal" href="project-ideas.html#stm-software-transactional-memory">STM (Software Transactional Memory)</a></li> <li class="toctree-l2"><a class="reference internal" href="project-ideas.html#introduce-new-benchmarks">Introduce new benchmarks</a></li> <li class="toctree-l2"><a class="reference internal" href="project-ideas.html#interfacing-with-c">Interfacing with C</a></li> </ul> </li> <li class="toctree-l1"><a class="reference internal" href="project-documentation.html">Project Documentation</a></li> <li class="toctree-l1"><a class="reference internal" href="project-documentation.html#source-code-documentation">Source Code Documentation</a></li> <li class="toctree-l1"><a class="reference internal" href="how-to-release.html">PyPy鈥檚 Release Process</a><ul> <li class="toctree-l2"><a class="reference internal" href="how-to-release.html#release-policy">Release Policy</a></li> <li class="toctree-l2"><a class="reference internal" href="how-to-release.html#how-to-create-a-pypy-release">How to Create a PyPy Release</a></li> <li class="toctree-l2"><a class="reference internal" href="how-to-release.html#release-steps">Release Steps</a></li> </ul> </li> </ul> </div> </div> <div class="section" id="further-resources"> <h2>Further resources<a class="headerlink" href="#further-resources" title="Permalink to this headline">露</a></h2> <div class="toctree-wrapper compound"> <ul> <li class="toctree-l1"><a class="reference internal" href="index-of-release-notes.html">Historical release notes</a></li> <li class="toctree-l1"><a class="reference internal" href="index-of-whatsnew.html">Changelogs</a></li> <li class="toctree-l1"><a class="reference internal" href="contributor.html">Contributors</a></li> <li class="toctree-l1"><a class="reference internal" href="glossary.html">Glossary</a></li> </ul> </div> </div> <div class="section" id="contact"> <span id="id2"></span><h2>Contact<a class="headerlink" href="#contact" title="Permalink to this headline">露</a></h2> <dl class="docutils"> <dt><a class="reference external" href="irc://irc.libera.chat/pypy">#pypy on irc.libera.chat</a></dt> <dd>Many of the core developers are hanging out here. You are welcome to join and ask questions (if they are not already answered in the <a class="reference internal" href="faq.html"><span class="doc">FAQ</span></a>). You can find logs of the channel <a class="reference external" href="https://quodlibet.duckdns.org/irc/pypy/latest.log.html#irc-end">here</a>.</dd> <dt><a class="reference external" href="https://mail.python.org/mailman/listinfo/pypy-dev">Development mailing list</a></dt> <dd>Development and conceptual discussions</dd> <dt><a class="reference external" href="https://mail.python.org/mailman/listinfo/pypy-commit">Commit mailing list</a></dt> <dd>Updates to code and documentation</dd> <dt><a class="reference external" href="https://github.com/pypy/pypy/issues/">Development bug/feature tracker</a></dt> <dd>Filing bugs and feature requests</dd> <dt>Meeting PyPy developers</dt> <dd>The PyPy developers are organizing sprints and presenting results at conferences all year round. They will be happy to meet in person with anyone interested in the project. Watch out for sprint announcements on the <a class="reference external" href="https://mail.python.org/mailman/listinfo/pypy-dev">development mailing list</a>.</dd> </dl> <p>Twitter handle <a class="reference external" href="https://twitter.com/pypyproject">#pypyproject</a></p> <p>Watch us on <a class="reference external" href="https://www.twitch.tv/pypyproject">twitch</a></p> </div> </div> <div class="section" id="indices-and-tables"> <h1>Indices and tables<a class="headerlink" href="#indices-and-tables" title="Permalink to this headline">露</a></h1> <ul class="simple"> <li><a class="reference internal" href="genindex.html"><span class="std std-ref">Index</span></a></li> <li><a class="reference internal" href="py-modindex.html"><span class="std std-ref">Module Index</span></a></li> <li><a class="reference internal" href="search.html"><span class="std std-ref">Search Page</span></a></li> </ul> </div> </div> </div> <footer><div class="rst-footer-buttons" role="navigation" aria-label="Footer"> <a href="introduction.html" class="btn btn-neutral float-right" title="What is PyPy?" accesskey="n" rel="next">Next <span class="fa fa-arrow-circle-right" aria-hidden="true"></span></a> </div> <hr/> <div role="contentinfo"> <p>© Copyright 2024, The PyPy Project. <span class="lastupdated">Last updated on Mar 11, 2025. </span></p> </div> Built with <a href="https://www.sphinx-doc.org/">Sphinx</a> using a <a href="https://github.com/readthedocs/sphinx_rtd_theme">theme</a> provided by <a href="https://readthedocs.org">Read the Docs</a>. </footer> </div> </div> </section> </div> <script> jQuery(function () { SphinxRtdTheme.Navigation.enable(true); }); </script> </body> </html>