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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="X-UA-Compatible" content="IE=Edge" /> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>Old Buffer Protocol — Python 3.6.7 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/sidebar.js"></script> <link rel="search" type="application/opensearchdescription+xml" title="Search within Python 3.6.7 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="Concrete Objects Layer" href="concrete.html" /> <link rel="prev" title="Buffer Protocol" href="buffer.html" /> <link rel="shortcut icon" type="image/png" href="../_static/py.png" /> <link rel="canonical" href="https://docs.python.org/3/c-api/objbuffer.html" /> <script type="text/javascript" src="../_static/copybutton.js"></script> </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="concrete.html" title="Concrete Objects Layer" accesskey="N">next</a> |</li> <li class="right" > <a href="buffer.html" title="Buffer Protocol" 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> <a href="../index.html">3.6.7 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="abstract.html" accesskey="U">Abstract Objects Layer</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="old-buffer-protocol"> <h1>Old Buffer Protocol<a class="headerlink" href="#old-buffer-protocol" title="Permalink to this headline">¶</a></h1> <div class="deprecated"> <p><span class="versionmodified">Deprecated since version 3.0.</span></p> </div> <p>These functions were part of the “old buffer protocol” API in Python 2. In Python 3, this protocol doesn’t exist anymore but the functions are still exposed to ease porting 2.x code. They act as a compatibility wrapper around the <a class="reference internal" href="buffer.html#bufferobjects"><span class="std std-ref">new buffer protocol</span></a>, but they don’t give you control over the lifetime of the resources acquired when a buffer is exported.</p> <p>Therefore, it is recommended that you call <a class="reference internal" href="buffer.html#c.PyObject_GetBuffer" title="PyObject_GetBuffer"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyObject_GetBuffer()</span></code></a> (or the <code class="docutils literal notranslate"><span class="pre">y*</span></code> or <code class="docutils literal notranslate"><span class="pre">w*</span></code> <a class="reference internal" href="arg.html#arg-parsing"><span class="std std-ref">format codes</span></a> with the <a class="reference internal" href="arg.html#c.PyArg_ParseTuple" title="PyArg_ParseTuple"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyArg_ParseTuple()</span></code></a> family of functions) to get a buffer view over an object, and <a class="reference internal" href="buffer.html#c.PyBuffer_Release" title="PyBuffer_Release"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyBuffer_Release()</span></code></a> when the buffer view can be released.</p> <dl class="function"> <dt id="c.PyObject_AsCharBuffer"> int <code class="descname">PyObject_AsCharBuffer</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *obj</em>, const char<em> **buffer</em>, Py_ssize_t<em> *buffer_len</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyObject_AsCharBuffer" title="Permalink to this definition">¶</a></dt> <dd><p>Returns a pointer to a read-only memory location usable as character-based input. The <em>obj</em> argument must support the single-segment character buffer interface. On success, returns <code class="docutils literal notranslate"><span class="pre">0</span></code>, sets <em>buffer</em> to the memory location and <em>buffer_len</em> to the buffer length. Returns <code class="docutils literal notranslate"><span class="pre">-1</span></code> and sets a <a class="reference internal" href="../library/exceptions.html#TypeError" title="TypeError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">TypeError</span></code></a> on error.</p> </dd></dl> <dl class="function"> <dt id="c.PyObject_AsReadBuffer"> int <code class="descname">PyObject_AsReadBuffer</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *obj</em>, const void<em> **buffer</em>, Py_ssize_t<em> *buffer_len</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyObject_AsReadBuffer" title="Permalink to this definition">¶</a></dt> <dd><p>Returns a pointer to a read-only memory location containing arbitrary data. The <em>obj</em> argument must support the single-segment readable buffer interface. On success, returns <code class="docutils literal notranslate"><span class="pre">0</span></code>, sets <em>buffer</em> to the memory location and <em>buffer_len</em> to the buffer length. Returns <code class="docutils literal notranslate"><span class="pre">-1</span></code> and sets a <a class="reference internal" href="../library/exceptions.html#TypeError" title="TypeError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">TypeError</span></code></a> on error.</p> </dd></dl> <dl class="function"> <dt id="c.PyObject_CheckReadBuffer"> int <code class="descname">PyObject_CheckReadBuffer</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *o</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyObject_CheckReadBuffer" title="Permalink to this definition">¶</a></dt> <dd><p>Returns <code class="docutils literal notranslate"><span class="pre">1</span></code> if <em>o</em> supports the single-segment readable buffer interface. Otherwise returns <code class="docutils literal notranslate"><span class="pre">0</span></code>.</p> </dd></dl> <dl class="function"> <dt id="c.PyObject_AsWriteBuffer"> int <code class="descname">PyObject_AsWriteBuffer</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *obj</em>, void<em> **buffer</em>, Py_ssize_t<em> *buffer_len</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyObject_AsWriteBuffer" title="Permalink to this definition">¶</a></dt> <dd><p>Returns a pointer to a writable memory location. The <em>obj</em> argument must support the single-segment, character buffer interface. On success, returns <code class="docutils literal notranslate"><span class="pre">0</span></code>, sets <em>buffer</em> to the memory location and <em>buffer_len</em> to the buffer length. Returns <code class="docutils literal notranslate"><span class="pre">-1</span></code> and sets a <a class="reference internal" href="../library/exceptions.html#TypeError" title="TypeError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">TypeError</span></code></a> on error.</p> </dd></dl> </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="buffer.html" title="previous chapter">Buffer Protocol</a></p> <h4>Next topic</h4> <p class="topless"><a href="concrete.html" title="next chapter">Concrete Objects Layer</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/3.6/Doc/c-api/objbuffer.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="concrete.html" title="Concrete Objects Layer" >next</a> |</li> <li class="right" > <a href="buffer.html" title="Buffer Protocol" >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> <a href="../index.html">3.6.7 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="abstract.html" >Abstract Objects Layer</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> 2001-2023, 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 Dec 18, 2023. <a href="../bugs.html">Found a bug</a>? <br /> Created using <a href="http://sphinx.pocoo.org/">Sphinx</a> 1.7.6. </div> </body> </html>