Edit File: object.html
<!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>Object Protocol — Python v2.6.6 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: '2.6.6', COLLAPSE_MODINDEX: false, FILE_SUFFIX: '.html', HAS_SOURCE: true }; </script> <script type="text/javascript" src="../_static/jquery.js"></script> <script type="text/javascript" src="../_static/doctools.js"></script> <link rel="search" type="application/opensearchdescription+xml" title="Search within Python v2.6.6 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 v2.6.6 documentation" href="../index.html" /> <link rel="up" title="Abstract Objects Layer" href="abstract.html" /> <link rel="next" title="Number Protocol" href="number.html" /> <link rel="prev" title="Abstract Objects Layer" href="abstract.html" /> <link rel="shortcut icon" type="image/png" href="../_static/py.png" /> </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="../modindex.html" title="Global Module Index" accesskey="M">modules</a> |</li> <li class="right" > <a href="number.html" title="Number Protocol" accesskey="N">next</a> |</li> <li class="right" > <a href="abstract.html" title="Abstract Objects Layer" accesskey="P">previous</a> |</li> <li><img src="../_static/py.png" alt="" style="vertical-align: middle; margin-top: -1px"/></li> <li><a href="../index.html">Python v2.6.6 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="object-protocol"> <span id="object"></span><h1>Object Protocol<a class="headerlink" href="#object-protocol" title="Permalink to this headline">¶</a></h1> <dl class="cfunction"> <dt id="PyObject_Print"> int <tt class="descname">PyObject_Print</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o</em>, FILE<em> *fp</em>, int<em> flags</em><big>)</big><a class="headerlink" href="#PyObject_Print" title="Permalink to this definition">¶</a></dt> <dd>Print an object <em>o</em>, on file <em>fp</em>. Returns <tt class="docutils literal"><span class="pre">-1</span></tt> on error. The flags argument is used to enable certain printing options. The only option currently supported is <tt class="xref docutils literal"><span class="pre">Py_PRINT_RAW</span></tt>; if given, the <a title="str" class="reference external" href="../library/functions.html#str"><tt class="xref docutils literal"><span class="pre">str()</span></tt></a> of the object is written instead of the <a title="repr" class="reference external" href="../library/functions.html#repr"><tt class="xref docutils literal"><span class="pre">repr()</span></tt></a>.</dd></dl> <dl class="cfunction"> <dt id="PyObject_HasAttr"> int <tt class="descname">PyObject_HasAttr</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o</em>, <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *attr_name</em><big>)</big><a class="headerlink" href="#PyObject_HasAttr" title="Permalink to this definition">¶</a></dt> <dd>Returns <tt class="docutils literal"><span class="pre">1</span></tt> if <em>o</em> has the attribute <em>attr_name</em>, and <tt class="docutils literal"><span class="pre">0</span></tt> otherwise. This is equivalent to the Python expression <tt class="docutils literal"><span class="pre">hasattr(o,</span> <span class="pre">attr_name)</span></tt>. This function always succeeds.</dd></dl> <dl class="cfunction"> <dt id="PyObject_HasAttrString"> int <tt class="descname">PyObject_HasAttrString</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o</em>, const char<em> *attr_name</em><big>)</big><a class="headerlink" href="#PyObject_HasAttrString" title="Permalink to this definition">¶</a></dt> <dd>Returns <tt class="docutils literal"><span class="pre">1</span></tt> if <em>o</em> has the attribute <em>attr_name</em>, and <tt class="docutils literal"><span class="pre">0</span></tt> otherwise. This is equivalent to the Python expression <tt class="docutils literal"><span class="pre">hasattr(o,</span> <span class="pre">attr_name)</span></tt>. This function always succeeds.</dd></dl> <dl class="cfunction"> <dt id="PyObject_GetAttr"> <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a>* <tt class="descname">PyObject_GetAttr</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o</em>, <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *attr_name</em><big>)</big><a class="headerlink" href="#PyObject_GetAttr" title="Permalink to this definition">¶</a></dt> <dd><em class="refcount">Return value: New reference.</em><p>Retrieve an attribute named <em>attr_name</em> from object <em>o</em>. Returns the attribute value on success, or <em>NULL</em> on failure. This is the equivalent of the Python expression <tt class="docutils literal"><span class="pre">o.attr_name</span></tt>.</p> </dd></dl> <dl class="cfunction"> <dt id="PyObject_GetAttrString"> <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a>* <tt class="descname">PyObject_GetAttrString</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o</em>, const char<em> *attr_name</em><big>)</big><a class="headerlink" href="#PyObject_GetAttrString" title="Permalink to this definition">¶</a></dt> <dd><em class="refcount">Return value: New reference.</em><p>Retrieve an attribute named <em>attr_name</em> from object <em>o</em>. Returns the attribute value on success, or <em>NULL</em> on failure. This is the equivalent of the Python expression <tt class="docutils literal"><span class="pre">o.attr_name</span></tt>.</p> </dd></dl> <dl class="cfunction"> <dt id="PyObject_GenericGetAttr"> <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a>* <tt class="descname">PyObject_GenericGetAttr</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o</em>, <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *name</em><big>)</big><a class="headerlink" href="#PyObject_GenericGetAttr" title="Permalink to this definition">¶</a></dt> <dd>Generic attribute getter function that is meant to be put into a type object’s <tt class="docutils literal"><span class="pre">tp_getattro</span></tt> slot. It looks for a descriptor in the dictionary of classes in the object’s MRO as well as an attribute in the object’s <tt class="xref docutils literal"><span class="pre">__dict__</span></tt> (if present). As outlined in <a class="reference external" href="../reference/datamodel.html#descriptors"><em>Implementing Descriptors</em></a>, data descriptors take preference over instance attributes, while non-data descriptors don’t. Otherwise, an <a title="exceptions.AttributeError" class="reference external" href="../library/exceptions.html#exceptions.AttributeError"><tt class="xref docutils literal"><span class="pre">AttributeError</span></tt></a> is raised.</dd></dl> <dl class="cfunction"> <dt id="PyObject_SetAttr"> int <tt class="descname">PyObject_SetAttr</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o</em>, <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *attr_name</em>, <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *v</em><big>)</big><a class="headerlink" href="#PyObject_SetAttr" title="Permalink to this definition">¶</a></dt> <dd>Set the value of the attribute named <em>attr_name</em>, for object <em>o</em>, to the value <em>v</em>. Returns <tt class="docutils literal"><span class="pre">-1</span></tt> on failure. This is the equivalent of the Python statement <tt class="docutils literal"><span class="pre">o.attr_name</span> <span class="pre">=</span> <span class="pre">v</span></tt>.</dd></dl> <dl class="cfunction"> <dt id="PyObject_SetAttrString"> int <tt class="descname">PyObject_SetAttrString</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o</em>, const char<em> *attr_name</em>, <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *v</em><big>)</big><a class="headerlink" href="#PyObject_SetAttrString" title="Permalink to this definition">¶</a></dt> <dd>Set the value of the attribute named <em>attr_name</em>, for object <em>o</em>, to the value <em>v</em>. Returns <tt class="docutils literal"><span class="pre">-1</span></tt> on failure. This is the equivalent of the Python statement <tt class="docutils literal"><span class="pre">o.attr_name</span> <span class="pre">=</span> <span class="pre">v</span></tt>.</dd></dl> <dl class="cfunction"> <dt id="PyObject_GenericSetAttr"> int <tt class="descname">PyObject_GenericSetAttr</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o</em>, <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *name</em>, <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *value</em><big>)</big><a class="headerlink" href="#PyObject_GenericSetAttr" title="Permalink to this definition">¶</a></dt> <dd>Generic attribute setter function that is meant to be put into a type object’s <tt class="docutils literal"><span class="pre">tp_setattro</span></tt> slot. It looks for a data descriptor in the dictionary of classes in the object’s MRO, and if found it takes preference over setting the attribute in the instance dictionary. Otherwise, the attribute is set in the object’s <tt class="xref docutils literal"><span class="pre">__dict__</span></tt> (if present). Otherwise, an <a title="exceptions.AttributeError" class="reference external" href="../library/exceptions.html#exceptions.AttributeError"><tt class="xref docutils literal"><span class="pre">AttributeError</span></tt></a> is raised and <tt class="docutils literal"><span class="pre">-1</span></tt> is returned.</dd></dl> <dl class="cfunction"> <dt id="PyObject_DelAttr"> int <tt class="descname">PyObject_DelAttr</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o</em>, <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *attr_name</em><big>)</big><a class="headerlink" href="#PyObject_DelAttr" title="Permalink to this definition">¶</a></dt> <dd>Delete attribute named <em>attr_name</em>, for object <em>o</em>. Returns <tt class="docutils literal"><span class="pre">-1</span></tt> on failure. This is the equivalent of the Python statement <tt class="docutils literal"><span class="pre">del</span> <span class="pre">o.attr_name</span></tt>.</dd></dl> <dl class="cfunction"> <dt id="PyObject_DelAttrString"> int <tt class="descname">PyObject_DelAttrString</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o</em>, const char<em> *attr_name</em><big>)</big><a class="headerlink" href="#PyObject_DelAttrString" title="Permalink to this definition">¶</a></dt> <dd>Delete attribute named <em>attr_name</em>, for object <em>o</em>. Returns <tt class="docutils literal"><span class="pre">-1</span></tt> on failure. This is the equivalent of the Python statement <tt class="docutils literal"><span class="pre">del</span> <span class="pre">o.attr_name</span></tt>.</dd></dl> <dl class="cfunction"> <dt id="PyObject_RichCompare"> <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a>* <tt class="descname">PyObject_RichCompare</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o1</em>, <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o2</em>, int<em> opid</em><big>)</big><a class="headerlink" href="#PyObject_RichCompare" title="Permalink to this definition">¶</a></dt> <dd><em class="refcount">Return value: New reference.</em><p>Compare the values of <em>o1</em> and <em>o2</em> using the operation specified by <em>opid</em>, which must be one of <tt class="xref docutils literal"><span class="pre">Py_LT</span></tt>, <tt class="xref docutils literal"><span class="pre">Py_LE</span></tt>, <tt class="xref docutils literal"><span class="pre">Py_EQ</span></tt>, <tt class="xref docutils literal"><span class="pre">Py_NE</span></tt>, <tt class="xref docutils literal"><span class="pre">Py_GT</span></tt>, or <tt class="xref docutils literal"><span class="pre">Py_GE</span></tt>, corresponding to <tt class="docutils literal"><span class="pre"><</span></tt>, <tt class="docutils literal"><span class="pre"><=</span></tt>, <tt class="docutils literal"><span class="pre">==</span></tt>, <tt class="docutils literal"><span class="pre">!=</span></tt>, <tt class="docutils literal"><span class="pre">></span></tt>, or <tt class="docutils literal"><span class="pre">>=</span></tt> respectively. This is the equivalent of the Python expression <tt class="docutils literal"><span class="pre">o1</span> <span class="pre">op</span> <span class="pre">o2</span></tt>, where <tt class="docutils literal"><span class="pre">op</span></tt> is the operator corresponding to <em>opid</em>. Returns the value of the comparison on success, or <em>NULL</em> on failure.</p> </dd></dl> <dl class="cfunction"> <dt id="PyObject_RichCompareBool"> int <tt class="descname">PyObject_RichCompareBool</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o1</em>, <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o2</em>, int<em> opid</em><big>)</big><a class="headerlink" href="#PyObject_RichCompareBool" title="Permalink to this definition">¶</a></dt> <dd>Compare the values of <em>o1</em> and <em>o2</em> using the operation specified by <em>opid</em>, which must be one of <tt class="xref docutils literal"><span class="pre">Py_LT</span></tt>, <tt class="xref docutils literal"><span class="pre">Py_LE</span></tt>, <tt class="xref docutils literal"><span class="pre">Py_EQ</span></tt>, <tt class="xref docutils literal"><span class="pre">Py_NE</span></tt>, <tt class="xref docutils literal"><span class="pre">Py_GT</span></tt>, or <tt class="xref docutils literal"><span class="pre">Py_GE</span></tt>, corresponding to <tt class="docutils literal"><span class="pre"><</span></tt>, <tt class="docutils literal"><span class="pre"><=</span></tt>, <tt class="docutils literal"><span class="pre">==</span></tt>, <tt class="docutils literal"><span class="pre">!=</span></tt>, <tt class="docutils literal"><span class="pre">></span></tt>, or <tt class="docutils literal"><span class="pre">>=</span></tt> respectively. Returns <tt class="docutils literal"><span class="pre">-1</span></tt> on error, <tt class="docutils literal"><span class="pre">0</span></tt> if the result is false, <tt class="docutils literal"><span class="pre">1</span></tt> otherwise. This is the equivalent of the Python expression <tt class="docutils literal"><span class="pre">o1</span> <span class="pre">op</span> <span class="pre">o2</span></tt>, where <tt class="docutils literal"><span class="pre">op</span></tt> is the operator corresponding to <em>opid</em>.</dd></dl> <dl class="cfunction"> <dt id="PyObject_Cmp"> int <tt class="descname">PyObject_Cmp</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o1</em>, <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o2</em>, int<em> *result</em><big>)</big><a class="headerlink" href="#PyObject_Cmp" title="Permalink to this definition">¶</a></dt> <dd><p id="index-123">Compare the values of <em>o1</em> and <em>o2</em> using a routine provided by <em>o1</em>, if one exists, otherwise with a routine provided by <em>o2</em>. The result of the comparison is returned in <em>result</em>. Returns <tt class="docutils literal"><span class="pre">-1</span></tt> on failure. This is the equivalent of the Python statement <tt class="docutils literal"><span class="pre">result</span> <span class="pre">=</span> <span class="pre">cmp(o1,</span> <span class="pre">o2)</span></tt>.</p> </dd></dl> <dl class="cfunction"> <dt id="PyObject_Compare"> int <tt class="descname">PyObject_Compare</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o1</em>, <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o2</em><big>)</big><a class="headerlink" href="#PyObject_Compare" title="Permalink to this definition">¶</a></dt> <dd><p id="index-124">Compare the values of <em>o1</em> and <em>o2</em> using a routine provided by <em>o1</em>, if one exists, otherwise with a routine provided by <em>o2</em>. Returns the result of the comparison on success. On error, the value returned is undefined; use <a title="PyErr_Occurred" class="reference external" href="exceptions.html#PyErr_Occurred"><tt class="xref docutils literal"><span class="pre">PyErr_Occurred()</span></tt></a> to detect an error. This is equivalent to the Python expression <tt class="docutils literal"><span class="pre">cmp(o1,</span> <span class="pre">o2)</span></tt>.</p> </dd></dl> <dl class="cfunction"> <dt id="PyObject_Repr"> <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a>* <tt class="descname">PyObject_Repr</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o</em><big>)</big><a class="headerlink" href="#PyObject_Repr" title="Permalink to this definition">¶</a></dt> <dd><em class="refcount">Return value: New reference.</em><p id="index-125">Compute a string representation of object <em>o</em>. Returns the string representation on success, <em>NULL</em> on failure. This is the equivalent of the Python expression <tt class="docutils literal"><span class="pre">repr(o)</span></tt>. Called by the <a title="repr" class="reference external" href="../library/functions.html#repr"><tt class="xref docutils literal"><span class="pre">repr()</span></tt></a> built-in function and by reverse quotes.</p> </dd></dl> <dl class="cfunction"> <dt id="PyObject_Str"> <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a>* <tt class="descname">PyObject_Str</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o</em><big>)</big><a class="headerlink" href="#PyObject_Str" title="Permalink to this definition">¶</a></dt> <dd><em class="refcount">Return value: New reference.</em><p id="index-126">Compute a string representation of object <em>o</em>. Returns the string representation on success, <em>NULL</em> on failure. This is the equivalent of the Python expression <tt class="docutils literal"><span class="pre">str(o)</span></tt>. Called by the <a title="str" class="reference external" href="../library/functions.html#str"><tt class="xref docutils literal"><span class="pre">str()</span></tt></a> built-in function and by the <a class="reference external" href="../reference/simple_stmts.html#print"><tt class="xref docutils literal"><span class="pre">print</span></tt></a> statement.</p> </dd></dl> <dl class="cfunction"> <dt id="PyObject_Bytes"> <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a>* <tt class="descname">PyObject_Bytes</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o</em><big>)</big><a class="headerlink" href="#PyObject_Bytes" title="Permalink to this definition">¶</a></dt> <dd><p id="index-127">Compute a bytes representation of object <em>o</em>. In 2.x, this is just a alias for <a title="PyObject_Str" class="reference internal" href="#PyObject_Str"><tt class="xref docutils literal"><span class="pre">PyObject_Str()</span></tt></a>.</p> </dd></dl> <dl class="cfunction"> <dt id="PyObject_Unicode"> <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a>* <tt class="descname">PyObject_Unicode</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o</em><big>)</big><a class="headerlink" href="#PyObject_Unicode" title="Permalink to this definition">¶</a></dt> <dd><em class="refcount">Return value: New reference.</em><p id="index-128">Compute a Unicode string representation of object <em>o</em>. Returns the Unicode string representation on success, <em>NULL</em> on failure. This is the equivalent of the Python expression <tt class="docutils literal"><span class="pre">unicode(o)</span></tt>. Called by the <a title="unicode" class="reference external" href="../library/functions.html#unicode"><tt class="xref docutils literal"><span class="pre">unicode()</span></tt></a> built-in function.</p> </dd></dl> <dl class="cfunction"> <dt id="PyObject_IsInstance"> int <tt class="descname">PyObject_IsInstance</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *inst</em>, <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *cls</em><big>)</big><a class="headerlink" href="#PyObject_IsInstance" title="Permalink to this definition">¶</a></dt> <dd><p>Returns <tt class="docutils literal"><span class="pre">1</span></tt> if <em>inst</em> is an instance of the class <em>cls</em> or a subclass of <em>cls</em>, or <tt class="docutils literal"><span class="pre">0</span></tt> if not. On error, returns <tt class="docutils literal"><span class="pre">-1</span></tt> and sets an exception. If <em>cls</em> is a type object rather than a class object, <a title="PyObject_IsInstance" class="reference internal" href="#PyObject_IsInstance"><tt class="xref docutils literal"><span class="pre">PyObject_IsInstance()</span></tt></a> returns <tt class="docutils literal"><span class="pre">1</span></tt> if <em>inst</em> is of type <em>cls</em>. If <em>cls</em> is a tuple, the check will be done against every entry in <em>cls</em>. The result will be <tt class="docutils literal"><span class="pre">1</span></tt> when at least one of the checks returns <tt class="docutils literal"><span class="pre">1</span></tt>, otherwise it will be <tt class="docutils literal"><span class="pre">0</span></tt>. If <em>inst</em> is not a class instance and <em>cls</em> is neither a type object, nor a class object, nor a tuple, <em>inst</em> must have a <tt class="xref docutils literal"><span class="pre">__class__</span></tt> attribute — the class relationship of the value of that attribute with <em>cls</em> will be used to determine the result of this function.</p> <p class="versionadded"> <span class="versionmodified">New in version 2.1.</span></p> <p class="versionchanged"> <span class="versionmodified">Changed in version 2.2: </span>Support for a tuple as the second argument added.</p> </dd></dl> <p>Subclass determination is done in a fairly straightforward way, but includes a wrinkle that implementors of extensions to the class system may want to be aware of. If <tt class="xref docutils literal"><span class="pre">A</span></tt> and <tt class="xref docutils literal"><span class="pre">B</span></tt> are class objects, <tt class="xref docutils literal"><span class="pre">B</span></tt> is a subclass of <tt class="xref docutils literal"><span class="pre">A</span></tt> if it inherits from <tt class="xref docutils literal"><span class="pre">A</span></tt> either directly or indirectly. If either is not a class object, a more general mechanism is used to determine the class relationship of the two objects. When testing if <em>B</em> is a subclass of <em>A</em>, if <em>A</em> is <em>B</em>, <a title="PyObject_IsSubclass" class="reference internal" href="#PyObject_IsSubclass"><tt class="xref docutils literal"><span class="pre">PyObject_IsSubclass()</span></tt></a> returns true. If <em>A</em> and <em>B</em> are different objects, <em>B</em>‘s <tt class="xref docutils literal"><span class="pre">__bases__</span></tt> attribute is searched in a depth-first fashion for <em>A</em> — the presence of the <tt class="xref docutils literal"><span class="pre">__bases__</span></tt> attribute is considered sufficient for this determination.</p> <dl class="cfunction"> <dt id="PyObject_IsSubclass"> int <tt class="descname">PyObject_IsSubclass</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *derived</em>, <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *cls</em><big>)</big><a class="headerlink" href="#PyObject_IsSubclass" title="Permalink to this definition">¶</a></dt> <dd><p>Returns <tt class="docutils literal"><span class="pre">1</span></tt> if the class <em>derived</em> is identical to or derived from the class <em>cls</em>, otherwise returns <tt class="docutils literal"><span class="pre">0</span></tt>. In case of an error, returns <tt class="docutils literal"><span class="pre">-1</span></tt>. If <em>cls</em> is a tuple, the check will be done against every entry in <em>cls</em>. The result will be <tt class="docutils literal"><span class="pre">1</span></tt> when at least one of the checks returns <tt class="docutils literal"><span class="pre">1</span></tt>, otherwise it will be <tt class="docutils literal"><span class="pre">0</span></tt>. If either <em>derived</em> or <em>cls</em> is not an actual class object (or tuple), this function uses the generic algorithm described above.</p> <p class="versionadded"> <span class="versionmodified">New in version 2.1.</span></p> <p class="versionchanged"> <span class="versionmodified">Changed in version 2.3: </span>Older versions of Python did not support a tuple as the second argument.</p> </dd></dl> <dl class="cfunction"> <dt id="PyCallable_Check"> int <tt class="descname">PyCallable_Check</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o</em><big>)</big><a class="headerlink" href="#PyCallable_Check" title="Permalink to this definition">¶</a></dt> <dd>Determine if the object <em>o</em> is callable. Return <tt class="docutils literal"><span class="pre">1</span></tt> if the object is callable and <tt class="docutils literal"><span class="pre">0</span></tt> otherwise. This function always succeeds.</dd></dl> <dl class="cfunction"> <dt id="PyObject_Call"> <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a>* <tt class="descname">PyObject_Call</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *callable_object</em>, <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *args</em>, <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *kw</em><big>)</big><a class="headerlink" href="#PyObject_Call" title="Permalink to this definition">¶</a></dt> <dd><em class="refcount">Return value: New reference.</em><p id="index-129">Call a callable Python object <em>callable_object</em>, with arguments given by the tuple <em>args</em>, and named arguments given by the dictionary <em>kw</em>. If no named arguments are needed, <em>kw</em> may be <em>NULL</em>. <em>args</em> must not be <em>NULL</em>, use an empty tuple if no arguments are needed. Returns the result of the call on success, or <em>NULL</em> on failure. This is the equivalent of the Python expression <tt class="docutils literal"><span class="pre">apply(callable_object,</span> <span class="pre">args,</span> <span class="pre">kw)</span></tt> or <tt class="docutils literal"><span class="pre">callable_object(*args,</span> <span class="pre">**kw)</span></tt>.</p> <p class="versionadded"> <span class="versionmodified">New in version 2.2.</span></p> </dd></dl> <dl class="cfunction"> <dt id="PyObject_CallObject"> <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a>* <tt class="descname">PyObject_CallObject</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *callable_object</em>, <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *args</em><big>)</big><a class="headerlink" href="#PyObject_CallObject" title="Permalink to this definition">¶</a></dt> <dd><em class="refcount">Return value: New reference.</em><p id="index-130">Call a callable Python object <em>callable_object</em>, with arguments given by the tuple <em>args</em>. If no arguments are needed, then <em>args</em> may be <em>NULL</em>. Returns the result of the call on success, or <em>NULL</em> on failure. This is the equivalent of the Python expression <tt class="docutils literal"><span class="pre">apply(callable_object,</span> <span class="pre">args)</span></tt> or <tt class="docutils literal"><span class="pre">callable_object(*args)</span></tt>.</p> </dd></dl> <dl class="cfunction"> <dt id="PyObject_CallFunction"> <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a>* <tt class="descname">PyObject_CallFunction</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *callable</em>, char<em> *format</em>, ...<big>)</big><a class="headerlink" href="#PyObject_CallFunction" title="Permalink to this definition">¶</a></dt> <dd><em class="refcount">Return value: New reference.</em><p id="index-131">Call a callable Python object <em>callable</em>, with a variable number of C arguments. The C arguments are described using a <a title="Py_BuildValue" class="reference external" href="arg.html#Py_BuildValue"><tt class="xref docutils literal"><span class="pre">Py_BuildValue()</span></tt></a> style format string. The format may be <em>NULL</em>, indicating that no arguments are provided. Returns the result of the call on success, or <em>NULL</em> on failure. This is the equivalent of the Python expression <tt class="docutils literal"><span class="pre">apply(callable,</span> <span class="pre">args)</span></tt> or <tt class="docutils literal"><span class="pre">callable(*args)</span></tt>. Note that if you only pass <a title="PyObject" class="reference external" href="structures.html#PyObject"><tt class="xref docutils literal"><span class="pre">PyObject</span> <span class="pre">*</span></tt></a> args, <a title="PyObject_CallFunctionObjArgs" class="reference internal" href="#PyObject_CallFunctionObjArgs"><tt class="xref docutils literal"><span class="pre">PyObject_CallFunctionObjArgs()</span></tt></a> is a faster alternative.</p> </dd></dl> <dl class="cfunction"> <dt id="PyObject_CallMethod"> <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a>* <tt class="descname">PyObject_CallMethod</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o</em>, char<em> *method</em>, char<em> *format</em>, ...<big>)</big><a class="headerlink" href="#PyObject_CallMethod" title="Permalink to this definition">¶</a></dt> <dd><em class="refcount">Return value: New reference.</em><p>Call the method named <em>method</em> of object <em>o</em> with a variable number of C arguments. The C arguments are described by a <a title="Py_BuildValue" class="reference external" href="arg.html#Py_BuildValue"><tt class="xref docutils literal"><span class="pre">Py_BuildValue()</span></tt></a> format string that should produce a tuple. The format may be <em>NULL</em>, indicating that no arguments are provided. Returns the result of the call on success, or <em>NULL</em> on failure. This is the equivalent of the Python expression <tt class="docutils literal"><span class="pre">o.method(args)</span></tt>. Note that if you only pass <a title="PyObject" class="reference external" href="structures.html#PyObject"><tt class="xref docutils literal"><span class="pre">PyObject</span> <span class="pre">*</span></tt></a> args, <a title="PyObject_CallMethodObjArgs" class="reference internal" href="#PyObject_CallMethodObjArgs"><tt class="xref docutils literal"><span class="pre">PyObject_CallMethodObjArgs()</span></tt></a> is a faster alternative.</p> </dd></dl> <dl class="cfunction"> <dt id="PyObject_CallFunctionObjArgs"> <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a>* <tt class="descname">PyObject_CallFunctionObjArgs</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *callable</em>, ..., NULL<big>)</big><a class="headerlink" href="#PyObject_CallFunctionObjArgs" title="Permalink to this definition">¶</a></dt> <dd><em class="refcount">Return value: New reference.</em><p>Call a callable Python object <em>callable</em>, with a variable number of <a title="PyObject" class="reference external" href="structures.html#PyObject"><tt class="xref docutils literal"><span class="pre">PyObject*</span></tt></a> arguments. The arguments are provided as a variable number of parameters followed by <em>NULL</em>. Returns the result of the call on success, or <em>NULL</em> on failure.</p> <p class="versionadded"> <span class="versionmodified">New in version 2.2.</span></p> </dd></dl> <dl class="cfunction"> <dt id="PyObject_CallMethodObjArgs"> <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a>* <tt class="descname">PyObject_CallMethodObjArgs</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o</em>, <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *name</em>, ..., NULL<big>)</big><a class="headerlink" href="#PyObject_CallMethodObjArgs" title="Permalink to this definition">¶</a></dt> <dd><em class="refcount">Return value: New reference.</em><p>Calls a method of the object <em>o</em>, where the name of the method is given as a Python string object in <em>name</em>. It is called with a variable number of <a title="PyObject" class="reference external" href="structures.html#PyObject"><tt class="xref docutils literal"><span class="pre">PyObject*</span></tt></a> arguments. The arguments are provided as a variable number of parameters followed by <em>NULL</em>. Returns the result of the call on success, or <em>NULL</em> on failure.</p> <p class="versionadded"> <span class="versionmodified">New in version 2.2.</span></p> </dd></dl> <dl class="cfunction"> <dt id="PyObject_Hash"> long <tt class="descname">PyObject_Hash</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o</em><big>)</big><a class="headerlink" href="#PyObject_Hash" title="Permalink to this definition">¶</a></dt> <dd><p id="index-132">Compute and return the hash value of an object <em>o</em>. On failure, return <tt class="docutils literal"><span class="pre">-1</span></tt>. This is the equivalent of the Python expression <tt class="docutils literal"><span class="pre">hash(o)</span></tt>.</p> </dd></dl> <dl class="cfunction"> <dt id="PyObject_HashNotImplemented"> long <tt class="descname">PyObject_HashNotImplemented</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o</em><big>)</big><a class="headerlink" href="#PyObject_HashNotImplemented" title="Permalink to this definition">¶</a></dt> <dd><p>Set a <a title="exceptions.TypeError" class="reference external" href="../library/exceptions.html#exceptions.TypeError"><tt class="xref docutils literal"><span class="pre">TypeError</span></tt></a> indicating that <tt class="docutils literal"><span class="pre">type(o)</span></tt> is not hashable and return <tt class="docutils literal"><span class="pre">-1</span></tt>. This function receives special treatment when stored in a <tt class="docutils literal"><span class="pre">tp_hash</span></tt> slot, allowing a type to explicitly indicate to the interpreter that it is not hashable.</p> <p class="versionadded"> <span class="versionmodified">New in version 2.6.</span></p> </dd></dl> <dl class="cfunction"> <dt id="PyObject_IsTrue"> int <tt class="descname">PyObject_IsTrue</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o</em><big>)</big><a class="headerlink" href="#PyObject_IsTrue" title="Permalink to this definition">¶</a></dt> <dd>Returns <tt class="docutils literal"><span class="pre">1</span></tt> if the object <em>o</em> is considered to be true, and <tt class="docutils literal"><span class="pre">0</span></tt> otherwise. This is equivalent to the Python expression <tt class="docutils literal"><span class="pre">not</span> <span class="pre">not</span> <span class="pre">o</span></tt>. On failure, return <tt class="docutils literal"><span class="pre">-1</span></tt>.</dd></dl> <dl class="cfunction"> <dt id="PyObject_Not"> int <tt class="descname">PyObject_Not</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o</em><big>)</big><a class="headerlink" href="#PyObject_Not" title="Permalink to this definition">¶</a></dt> <dd>Returns <tt class="docutils literal"><span class="pre">0</span></tt> if the object <em>o</em> is considered to be true, and <tt class="docutils literal"><span class="pre">1</span></tt> otherwise. This is equivalent to the Python expression <tt class="docutils literal"><span class="pre">not</span> <span class="pre">o</span></tt>. On failure, return <tt class="docutils literal"><span class="pre">-1</span></tt>.</dd></dl> <dl class="cfunction"> <dt id="PyObject_Type"> <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a>* <tt class="descname">PyObject_Type</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o</em><big>)</big><a class="headerlink" href="#PyObject_Type" title="Permalink to this definition">¶</a></dt> <dd><em class="refcount">Return value: New reference.</em><p id="index-133">When <em>o</em> is non-<em>NULL</em>, returns a type object corresponding to the object type of object <em>o</em>. On failure, raises <a title="exceptions.SystemError" class="reference external" href="../library/exceptions.html#exceptions.SystemError"><tt class="xref docutils literal"><span class="pre">SystemError</span></tt></a> and returns <em>NULL</em>. This is equivalent to the Python expression <tt class="docutils literal"><span class="pre">type(o)</span></tt>. This function increments the reference count of the return value. There’s really no reason to use this function instead of the common expression <tt class="docutils literal"><span class="pre">o->ob_type</span></tt>, which returns a pointer of type <a title="PyTypeObject" class="reference external" href="type.html#PyTypeObject"><tt class="xref docutils literal"><span class="pre">PyTypeObject*</span></tt></a>, except when the incremented reference count is needed.</p> </dd></dl> <dl class="cfunction"> <dt id="PyObject_TypeCheck"> int <tt class="descname">PyObject_TypeCheck</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o</em>, <a title="PyTypeObject" class="reference external" href="type.html#PyTypeObject">PyTypeObject</a><em> *type</em><big>)</big><a class="headerlink" href="#PyObject_TypeCheck" title="Permalink to this definition">¶</a></dt> <dd><p>Return true if the object <em>o</em> is of type <em>type</em> or a subtype of <em>type</em>. Both parameters must be non-<em>NULL</em>.</p> <p class="versionadded"> <span class="versionmodified">New in version 2.2.</span></p> </dd></dl> <dl class="cfunction"> <dt id="PyObject_Length"> Py_ssize_t <tt class="descname">PyObject_Length</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o</em><big>)</big><a class="headerlink" href="#PyObject_Length" title="Permalink to this definition">¶</a></dt> <dt id="PyObject_Size"> Py_ssize_t <tt class="descname">PyObject_Size</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o</em><big>)</big><a class="headerlink" href="#PyObject_Size" title="Permalink to this definition">¶</a></dt> <dd><p id="index-134">Return the length of object <em>o</em>. If the object <em>o</em> provides either the sequence and mapping protocols, the sequence length is returned. On error, <tt class="docutils literal"><span class="pre">-1</span></tt> is returned. This is the equivalent to the Python expression <tt class="docutils literal"><span class="pre">len(o)</span></tt>.</p> <p class="versionchanged"> <span class="versionmodified">Changed in version 2.5: </span>These functions returned an <tt class="xref docutils literal"><span class="pre">int</span></tt> type. This might require changes in your code for properly supporting 64-bit systems.</p> </dd></dl> <dl class="cfunction"> <dt id="PyObject_GetItem"> <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a>* <tt class="descname">PyObject_GetItem</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o</em>, <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *key</em><big>)</big><a class="headerlink" href="#PyObject_GetItem" title="Permalink to this definition">¶</a></dt> <dd><em class="refcount">Return value: New reference.</em><p>Return element of <em>o</em> corresponding to the object <em>key</em> or <em>NULL</em> on failure. This is the equivalent of the Python expression <tt class="docutils literal"><span class="pre">o[key]</span></tt>.</p> </dd></dl> <dl class="cfunction"> <dt id="PyObject_SetItem"> int <tt class="descname">PyObject_SetItem</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o</em>, <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *key</em>, <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *v</em><big>)</big><a class="headerlink" href="#PyObject_SetItem" title="Permalink to this definition">¶</a></dt> <dd>Map the object <em>key</em> to the value <em>v</em>. Returns <tt class="docutils literal"><span class="pre">-1</span></tt> on failure. This is the equivalent of the Python statement <tt class="docutils literal"><span class="pre">o[key]</span> <span class="pre">=</span> <span class="pre">v</span></tt>.</dd></dl> <dl class="cfunction"> <dt id="PyObject_DelItem"> int <tt class="descname">PyObject_DelItem</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o</em>, <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *key</em><big>)</big><a class="headerlink" href="#PyObject_DelItem" title="Permalink to this definition">¶</a></dt> <dd>Delete the mapping for <em>key</em> from <em>o</em>. Returns <tt class="docutils literal"><span class="pre">-1</span></tt> on failure. This is the equivalent of the Python statement <tt class="docutils literal"><span class="pre">del</span> <span class="pre">o[key]</span></tt>.</dd></dl> <dl class="cfunction"> <dt id="PyObject_AsFileDescriptor"> int <tt class="descname">PyObject_AsFileDescriptor</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o</em><big>)</big><a class="headerlink" href="#PyObject_AsFileDescriptor" title="Permalink to this definition">¶</a></dt> <dd>Derives a file descriptor from a Python object. If the object is an integer or long integer, its value is returned. If not, the object’s <tt class="xref docutils literal"><span class="pre">fileno()</span></tt> method is called if it exists; the method must return an integer or long integer, which is returned as the file descriptor value. Returns <tt class="docutils literal"><span class="pre">-1</span></tt> on failure.</dd></dl> <dl class="cfunction"> <dt id="PyObject_Dir"> <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a>* <tt class="descname">PyObject_Dir</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o</em><big>)</big><a class="headerlink" href="#PyObject_Dir" title="Permalink to this definition">¶</a></dt> <dd><em class="refcount">Return value: New reference.</em><p>This is equivalent to the Python expression <tt class="docutils literal"><span class="pre">dir(o)</span></tt>, returning a (possibly empty) list of strings appropriate for the object argument, or <em>NULL</em> if there was an error. If the argument is <em>NULL</em>, this is like the Python <tt class="docutils literal"><span class="pre">dir()</span></tt>, returning the names of the current locals; in this case, if no execution frame is active then <em>NULL</em> is returned but <a title="PyErr_Occurred" class="reference external" href="exceptions.html#PyErr_Occurred"><tt class="xref docutils literal"><span class="pre">PyErr_Occurred()</span></tt></a> will return false.</p> </dd></dl> <dl class="cfunction"> <dt id="PyObject_GetIter"> <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a>* <tt class="descname">PyObject_GetIter</tt><big>(</big><a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *o</em><big>)</big><a class="headerlink" href="#PyObject_GetIter" title="Permalink to this definition">¶</a></dt> <dd><em class="refcount">Return value: New reference.</em><p>This is equivalent to the Python expression <tt class="docutils literal"><span class="pre">iter(o)</span></tt>. It returns a new iterator for the object argument, or the object itself if the object is already an iterator. Raises <a title="exceptions.TypeError" class="reference external" href="../library/exceptions.html#exceptions.TypeError"><tt class="xref docutils literal"><span class="pre">TypeError</span></tt></a> and returns <em>NULL</em> if the object cannot be iterated.</p> </dd></dl> </div> </div> </div> </div> <div class="sphinxsidebar"> <div class="sphinxsidebarwrapper"> <h4>Previous topic</h4> <p class="topless"><a href="abstract.html" title="previous chapter">Abstract Objects Layer</a></p> <h4>Next topic</h4> <p class="topless"><a href="number.html" title="next chapter">Number Protocol</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/object.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" size="18" /> <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="../modindex.html" title="Global Module Index" >modules</a> |</li> <li class="right" > <a href="number.html" title="Number Protocol" >next</a> |</li> <li class="right" > <a href="abstract.html" title="Abstract Objects Layer" >previous</a> |</li> <li><img src="../_static/py.png" alt="" style="vertical-align: middle; margin-top: -1px"/></li> <li><a href="../index.html">Python v2.6.6 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> 1990-2011, 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 Jul 20, 2011. <a href="../bugs.html">Found a bug</a>? <br /> Created using <a href="http://sphinx.pocoo.org/">Sphinx</a> 0.6.6. </div> </body> </html>
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