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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="Content-Type" content="text/html; charset=utf-8" /> <title>Old Buffer Protocol — Python 2.7.5 documentation</title> <link rel="stylesheet" href="../_static/default.css" type="text/css" /> <link rel="stylesheet" href="../_static/pygments.css" type="text/css" /> <script type="text/javascript"> var DOCUMENTATION_OPTIONS = { URL_ROOT: '../', VERSION: '2.7.5', COLLAPSE_INDEX: false, FILE_SUFFIX: '.html', HAS_SOURCE: true }; </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 2.7.5 documentation" href="../_static/opensearch.xml"/> <link rel="author" title="About these documents" href="../about.html" /> <link rel="copyright" title="Copyright" href="../copyright.html" /> <link rel="top" title="Python 2.7.5 documentation" href="../index.html" /> <link rel="up" title="Abstract Objects Layer" href="abstract.html" /> <link rel="next" title="Concrete Objects Layer" href="concrete.html" /> <link rel="prev" title="Iterator Protocol" href="iter.html" /> <link rel="shortcut icon" type="image/png" href="../_static/py.png" /> <script type="text/javascript" src="../_static/copybutton.js"></script> </head> <body> <div class="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="concrete.html" title="Concrete Objects Layer" accesskey="N">next</a> |</li> <li class="right" > <a href="iter.html" title="Iterator Protocol" accesskey="P">previous</a> |</li> <li><img src="../_static/py.png" alt="" style="vertical-align: middle; margin-top: -1px"/></li> <li><a href="http://www.python.org/">Python</a> »</li> <li> <a href="../index.html">Python 2.7.5 documentation</a> » </li> <li><a href="index.html" >Python/C API Reference Manual</a> »</li> <li><a href="abstract.html" accesskey="U">Abstract Objects Layer</a> »</li> </ul> </div> <div class="document"> <div class="documentwrapper"> <div class="bodywrapper"> <div class="body"> <div class="section" id="old-buffer-protocol"> <span id="abstract-buffer"></span><h1>Old Buffer Protocol<a class="headerlink" href="#old-buffer-protocol" title="Permalink to this headline">¶</a></h1> <p>This section describes the legacy buffer protocol, which has been introduced in Python 1.6. It is still supported but deprecated in the Python 2.x series. Python 3 introduces a new buffer protocol which fixes weaknesses and shortcomings of the protocol, and has been backported to Python 2.6. See <a class="reference internal" href="buffer.html#bufferobjects"><em>Buffers and Memoryview Objects</em></a> for more information.</p> <dl class="function"> <dt id="PyObject_AsCharBuffer"> int <tt class="descname">PyObject_AsCharBuffer</tt><big>(</big><a class="reference internal" href="structures.html#PyObject" title="PyObject">PyObject</a><em> *obj</em>, const char<em> **buffer</em>, Py_ssize_t<em> *buffer_len</em><big>)</big><a class="headerlink" href="#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 <tt class="docutils literal"><span class="pre">0</span></tt>, sets <em>buffer</em> to the memory location and <em>buffer_len</em> to the buffer length. Returns <tt class="docutils literal"><span class="pre">-1</span></tt> and sets a <a class="reference internal" href="../library/exceptions.html#exceptions.TypeError" title="exceptions.TypeError"><tt class="xref py py-exc docutils literal"><span class="pre">TypeError</span></tt></a> on error.</p> <p class="versionadded"> <span class="versionmodified">New in version 1.6.</span></p> <p class="versionchanged"> <span class="versionmodified">Changed in version 2.5: </span>This function used an <tt class="xref c c-type docutils literal"><span class="pre">int</span> <span class="pre">*</span></tt> type for <em>buffer_len</em>. This might require changes in your code for properly supporting 64-bit systems.</p> </dd></dl> <dl class="function"> <dt id="PyObject_AsReadBuffer"> int <tt class="descname">PyObject_AsReadBuffer</tt><big>(</big><a class="reference internal" href="structures.html#PyObject" title="PyObject">PyObject</a><em> *obj</em>, const void<em> **buffer</em>, Py_ssize_t<em> *buffer_len</em><big>)</big><a class="headerlink" href="#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 <tt class="docutils literal"><span class="pre">0</span></tt>, sets <em>buffer</em> to the memory location and <em>buffer_len</em> to the buffer length. Returns <tt class="docutils literal"><span class="pre">-1</span></tt> and sets a <a class="reference internal" href="../library/exceptions.html#exceptions.TypeError" title="exceptions.TypeError"><tt class="xref py py-exc docutils literal"><span class="pre">TypeError</span></tt></a> on error.</p> <p class="versionadded"> <span class="versionmodified">New in version 1.6.</span></p> <p class="versionchanged"> <span class="versionmodified">Changed in version 2.5: </span>This function used an <tt class="xref c c-type docutils literal"><span class="pre">int</span> <span class="pre">*</span></tt> type for <em>buffer_len</em>. This might require changes in your code for properly supporting 64-bit systems.</p> </dd></dl> <dl class="function"> <dt id="PyObject_CheckReadBuffer"> int <tt class="descname">PyObject_CheckReadBuffer</tt><big>(</big><a class="reference internal" href="structures.html#PyObject" title="PyObject">PyObject</a><em> *o</em><big>)</big><a class="headerlink" href="#PyObject_CheckReadBuffer" title="Permalink to this definition">¶</a></dt> <dd><p>Returns <tt class="docutils literal"><span class="pre">1</span></tt> if <em>o</em> supports the single-segment readable buffer interface. Otherwise returns <tt class="docutils literal"><span class="pre">0</span></tt>.</p> <p class="versionadded"> <span class="versionmodified">New in version 2.2.</span></p> </dd></dl> <dl class="function"> <dt id="PyObject_AsWriteBuffer"> int <tt class="descname">PyObject_AsWriteBuffer</tt><big>(</big><a class="reference internal" href="structures.html#PyObject" title="PyObject">PyObject</a><em> *obj</em>, void<em> **buffer</em>, Py_ssize_t<em> *buffer_len</em><big>)</big><a class="headerlink" href="#PyObject_AsWriteBuffer" title="Permalink to this definition">¶</a></dt> <dd><p>Returns a pointer to a writeable memory location. The <em>obj</em> argument must support the single-segment, character buffer interface. On success, returns <tt class="docutils literal"><span class="pre">0</span></tt>, sets <em>buffer</em> to the memory location and <em>buffer_len</em> to the buffer length. Returns <tt class="docutils literal"><span class="pre">-1</span></tt> and sets a <a class="reference internal" href="../library/exceptions.html#exceptions.TypeError" title="exceptions.TypeError"><tt class="xref py py-exc docutils literal"><span class="pre">TypeError</span></tt></a> on error.</p> <p class="versionadded"> <span class="versionmodified">New in version 1.6.</span></p> <p class="versionchanged"> <span class="versionmodified">Changed in version 2.5: </span>This function used an <tt class="xref c c-type docutils literal"><span class="pre">int</span> <span class="pre">*</span></tt> type for <em>buffer_len</em>. This might require changes in your code for properly supporting 64-bit systems.</p> </dd></dl> </div> </div> </div> </div> <div class="sphinxsidebar"> <div class="sphinxsidebarwrapper"> <h4>Previous topic</h4> <p class="topless"><a href="iter.html" title="previous chapter">Iterator Protocol</a></p> <h4>Next topic</h4> <p class="topless"><a href="concrete.html" title="next chapter">Concrete Objects Layer</a></p> <h3>This Page</h3> <ul class="this-page-menu"> <li><a href="../bugs.html">Report a Bug</a></li> <li><a href="../_sources/c-api/objbuffer.txt" rel="nofollow">Show Source</a></li> </ul> <div id="searchbox" style="display: none"> <h3>Quick search</h3> <form class="search" action="../search.html" method="get"> <input 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> <p class="searchtip" style="font-size: 90%"> Enter search terms or a module, class or function name. </p> </div> <script type="text/javascript">$('#searchbox').show(0);</script> </div> </div> <div class="clearer"></div> </div> <div class="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="concrete.html" title="Concrete Objects Layer" >next</a> |</li> <li class="right" > <a href="iter.html" title="Iterator Protocol" >previous</a> |</li> <li><img src="../_static/py.png" alt="" style="vertical-align: middle; margin-top: -1px"/></li> <li><a href="http://www.python.org/">Python</a> »</li> <li> <a href="../index.html">Python 2.7.5 documentation</a> » </li> <li><a href="index.html" >Python/C API Reference Manual</a> »</li> <li><a href="abstract.html" >Abstract Objects Layer</a> »</li> </ul> </div> <div class="footer"> © <a href="../copyright.html">Copyright</a> 1990-2020, Python Software Foundation. <br /> The Python Software Foundation is a non-profit corporation. <a href="http://www.python.org/psf/donations/">Please donate.</a> <br /> Last updated on Oct 13, 2020. <a href="../bugs.html">Found a bug</a>? <br /> Created using <a href="http://sphinx.pocoo.org/">Sphinx</a> 1.1.3. </div> </body> </html>