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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>Cell Objects — 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="Code Objects" href="code.html" /> <link rel="prev" title="Instance Method Objects" href="method.html" /> <link rel="shortcut icon" type="image/png" href="../_static/py.png" /> <link rel="canonical" href="https://docs.python.org/3/c-api/cell.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="code.html" title="Code Objects" accesskey="N">next</a> |</li> <li class="right" > <a href="method.html" title="Instance Method Objects" 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="concrete.html" accesskey="U">Concrete 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="cell-objects"> <span id="id1"></span><h1>Cell Objects<a class="headerlink" href="#cell-objects" title="Permalink to this headline">¶</a></h1> <p>“Cell” objects are used to implement variables referenced by multiple scopes. For each such variable, a cell object is created to store the value; the local variables of each stack frame that references the value contains a reference to the cells from outer scopes which also use that variable. When the value is accessed, the value contained in the cell is used instead of the cell object itself. This de-referencing of the cell object requires support from the generated byte-code; these are not automatically de-referenced when accessed. Cell objects are not likely to be useful elsewhere.</p> <dl class="type"> <dt id="c.PyCellObject"> <code class="descname">PyCellObject</code><a class="headerlink" href="#c.PyCellObject" title="Permalink to this definition">¶</a></dt> <dd><p>The C structure used for cell objects.</p> </dd></dl> <dl class="var"> <dt id="c.PyCell_Type"> <a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject">PyTypeObject</a> <code class="descname">PyCell_Type</code><a class="headerlink" href="#c.PyCell_Type" title="Permalink to this definition">¶</a></dt> <dd><p>The type object corresponding to cell objects.</p> </dd></dl> <dl class="function"> <dt id="c.PyCell_Check"> int <code class="descname">PyCell_Check</code><span class="sig-paren">(</span>ob<span class="sig-paren">)</span><a class="headerlink" href="#c.PyCell_Check" title="Permalink to this definition">¶</a></dt> <dd><p>Return true if <em>ob</em> is a cell object; <em>ob</em> must not be <em>NULL</em>.</p> </dd></dl> <dl class="function"> <dt id="c.PyCell_New"> <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a>* <code class="descname">PyCell_New</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *ob</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyCell_New" title="Permalink to this definition">¶</a></dt> <dd><em class="refcount">Return value: New reference.</em><p>Create and return a new cell object containing the value <em>ob</em>. The parameter may be <em>NULL</em>.</p> </dd></dl> <dl class="function"> <dt id="c.PyCell_Get"> <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a>* <code class="descname">PyCell_Get</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *cell</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyCell_Get" title="Permalink to this definition">¶</a></dt> <dd><em class="refcount">Return value: New reference.</em><p>Return the contents of the cell <em>cell</em>.</p> </dd></dl> <dl class="function"> <dt id="c.PyCell_GET"> <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a>* <code class="descname">PyCell_GET</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *cell</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyCell_GET" title="Permalink to this definition">¶</a></dt> <dd><em class="refcount">Return value: Borrowed reference.</em><p>Return the contents of the cell <em>cell</em>, but without checking that <em>cell</em> is non-<em>NULL</em> and a cell object.</p> </dd></dl> <dl class="function"> <dt id="c.PyCell_Set"> int <code class="descname">PyCell_Set</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *cell</em>, <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *value</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyCell_Set" title="Permalink to this definition">¶</a></dt> <dd><p>Set the contents of the cell object <em>cell</em> to <em>value</em>. This releases the reference to any current content of the cell. <em>value</em> may be <em>NULL</em>. <em>cell</em> must be non-<em>NULL</em>; if it is not a cell object, <code class="docutils literal notranslate"><span class="pre">-1</span></code> will be returned. On success, <code class="docutils literal notranslate"><span class="pre">0</span></code> will be returned.</p> </dd></dl> <dl class="function"> <dt id="c.PyCell_SET"> void <code class="descname">PyCell_SET</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *cell</em>, <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *value</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyCell_SET" title="Permalink to this definition">¶</a></dt> <dd><p>Sets the value of the cell object <em>cell</em> to <em>value</em>. No reference counts are adjusted, and no checks are made for safety; <em>cell</em> must be non-<em>NULL</em> and must be a cell object.</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="method.html" title="previous chapter">Instance Method Objects</a></p> <h4>Next topic</h4> <p class="topless"><a href="code.html" title="next chapter">Code Objects</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/cell.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="code.html" title="Code Objects" >next</a> |</li> <li class="right" > <a href="method.html" title="Instance Method Objects" >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="concrete.html" >Concrete 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> 2001-2021, 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 Aug 25, 2021. <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>