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<div class="section" id="allocating-objects-on-the-heap">
<span id="allocating-objects"></span><h1>Allocating Objects on the Heap<a class="headerlink" href="#allocating-objects-on-the-heap" title="Permalink to this headline">¶</a></h1>
<dl class="function">
<dt id="_PyObject_New">
<a class="reference internal" href="structures.html#PyObject" title="PyObject">PyObject</a>* <tt class="descname">_PyObject_New</tt><big>(</big><a class="reference internal" href="type.html#PyTypeObject" title="PyTypeObject">PyTypeObject</a><em> *type</em><big>)</big><a class="headerlink" href="#_PyObject_New" title="Permalink to this definition">¶</a></dt>
<dd><em class="refcount">Return value: New reference.</em></dd></dl>
<dl class="function">
<dt id="_PyObject_NewVar">
<a class="reference internal" href="structures.html#PyVarObject" title="PyVarObject">PyVarObject</a>* <tt class="descname">_PyObject_NewVar</tt><big>(</big><a class="reference internal" href="type.html#PyTypeObject" title="PyTypeObject">PyTypeObject</a><em> *type</em>, Py_ssize_t<em> size</em><big>)</big><a class="headerlink" href="#_PyObject_NewVar" title="Permalink to this definition">¶</a></dt>
<dd><em class="refcount">Return value: New reference.</em><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></tt> type for <em>size</em>. This might require
changes in your code for properly supporting 64-bit systems.</p>
</dd></dl>
<dl class="function">
<dt id="_PyObject_Del">
void <tt class="descname">_PyObject_Del</tt><big>(</big><a class="reference internal" href="structures.html#PyObject" title="PyObject">PyObject</a><em> *op</em><big>)</big><a class="headerlink" href="#_PyObject_Del" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
<dl class="function">
<dt id="PyObject_Init">
<a class="reference internal" href="structures.html#PyObject" title="PyObject">PyObject</a>* <tt class="descname">PyObject_Init</tt><big>(</big><a class="reference internal" href="structures.html#PyObject" title="PyObject">PyObject</a><em> *op</em>, <a class="reference internal" href="type.html#PyTypeObject" title="PyTypeObject">PyTypeObject</a><em> *type</em><big>)</big><a class="headerlink" href="#PyObject_Init" title="Permalink to this definition">¶</a></dt>
<dd><em class="refcount">Return value: Borrowed reference.</em><p>Initialize a newly-allocated object <em>op</em> with its type and initial
reference. Returns the initialized object. If <em>type</em> indicates that the
object participates in the cyclic garbage detector, it is added to the
detector’s set of observed objects. Other fields of the object are not
affected.</p>
</dd></dl>
<dl class="function">
<dt id="PyObject_InitVar">
<a class="reference internal" href="structures.html#PyVarObject" title="PyVarObject">PyVarObject</a>* <tt class="descname">PyObject_InitVar</tt><big>(</big><a class="reference internal" href="structures.html#PyVarObject" title="PyVarObject">PyVarObject</a><em> *op</em>, <a class="reference internal" href="type.html#PyTypeObject" title="PyTypeObject">PyTypeObject</a><em> *type</em>, Py_ssize_t<em> size</em><big>)</big><a class="headerlink" href="#PyObject_InitVar" title="Permalink to this definition">¶</a></dt>
<dd><em class="refcount">Return value: Borrowed reference.</em><p>This does everything <a class="reference internal" href="#PyObject_Init" title="PyObject_Init"><tt class="xref c c-func docutils literal"><span class="pre">PyObject_Init()</span></tt></a> does, and also initializes the
length information for a variable-size object.</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></tt> type for <em>size</em>. This might require
changes in your code for properly supporting 64-bit systems.</p>
</dd></dl>
<dl class="function">
<dt id="PyObject_New">
TYPE* <tt class="descname">PyObject_New</tt><big>(</big>TYPE, <a class="reference internal" href="type.html#PyTypeObject" title="PyTypeObject">PyTypeObject</a><em> *type</em><big>)</big><a class="headerlink" href="#PyObject_New" title="Permalink to this definition">¶</a></dt>
<dd><em class="refcount">Return value: New reference.</em><p>Allocate a new Python object using the C structure type <em>TYPE</em> and the
Python type object <em>type</em>. Fields not defined by the Python object header
are not initialized; the object’s reference count will be one. The size of
the memory allocation is determined from the <tt class="xref py py-attr docutils literal"><span class="pre">tp_basicsize</span></tt> field of
the type object.</p>
</dd></dl>
<dl class="function">
<dt id="PyObject_NewVar">
TYPE* <tt class="descname">PyObject_NewVar</tt><big>(</big>TYPE, <a class="reference internal" href="type.html#PyTypeObject" title="PyTypeObject">PyTypeObject</a><em> *type</em>, Py_ssize_t<em> size</em><big>)</big><a class="headerlink" href="#PyObject_NewVar" title="Permalink to this definition">¶</a></dt>
<dd><em class="refcount">Return value: New reference.</em><p>Allocate a new Python object using the C structure type <em>TYPE</em> and the
Python type object <em>type</em>. Fields not defined by the Python object header
are not initialized. The allocated memory allows for the <em>TYPE</em> structure
plus <em>size</em> fields of the size given by the <tt class="xref py py-attr docutils literal"><span class="pre">tp_itemsize</span></tt> field of
<em>type</em>. This is useful for implementing objects like tuples, which are
able to determine their size at construction time. Embedding the array of
fields into the same allocation decreases the number of allocations,
improving the memory management efficiency.</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></tt> type for <em>size</em>. This might require
changes in your code for properly supporting 64-bit systems.</p>
</dd></dl>
<dl class="function">
<dt id="PyObject_Del">
void <tt class="descname">PyObject_Del</tt><big>(</big><a class="reference internal" href="structures.html#PyObject" title="PyObject">PyObject</a><em> *op</em><big>)</big><a class="headerlink" href="#PyObject_Del" title="Permalink to this definition">¶</a></dt>
<dd><p>Releases memory allocated to an object using <a class="reference internal" href="#PyObject_New" title="PyObject_New"><tt class="xref c c-func docutils literal"><span class="pre">PyObject_New()</span></tt></a> or
<a class="reference internal" href="#PyObject_NewVar" title="PyObject_NewVar"><tt class="xref c c-func docutils literal"><span class="pre">PyObject_NewVar()</span></tt></a>. This is normally called from the
<tt class="xref py py-attr docutils literal"><span class="pre">tp_dealloc</span></tt> handler specified in the object’s type. The fields of
the object should not be accessed after this call as the memory is no
longer a valid Python object.</p>
</dd></dl>
<dl class="function">
<dt id="Py_InitModule">
<a class="reference internal" href="structures.html#PyObject" title="PyObject">PyObject</a>* <tt class="descname">Py_InitModule</tt><big>(</big>char<em> *name</em>, <a class="reference internal" href="structures.html#PyMethodDef" title="PyMethodDef">PyMethodDef</a><em> *methods</em><big>)</big><a class="headerlink" href="#Py_InitModule" title="Permalink to this definition">¶</a></dt>
<dd><em class="refcount">Return value: Borrowed reference.</em><p>Create a new module object based on a name and table of functions,
returning the new module object.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.3: </span>Older versions of Python did not support <em>NULL</em> as the value for the
<em>methods</em> argument.</p>
</dd></dl>
<dl class="function">
<dt id="Py_InitModule3">
<a class="reference internal" href="structures.html#PyObject" title="PyObject">PyObject</a>* <tt class="descname">Py_InitModule3</tt><big>(</big>char<em> *name</em>, <a class="reference internal" href="structures.html#PyMethodDef" title="PyMethodDef">PyMethodDef</a><em> *methods</em>, char<em> *doc</em><big>)</big><a class="headerlink" href="#Py_InitModule3" title="Permalink to this definition">¶</a></dt>
<dd><em class="refcount">Return value: Borrowed reference.</em><p>Create a new module object based on a name and table of functions,
returning the new module object. If <em>doc</em> is non-<em>NULL</em>, it will be used
to define the docstring for the module.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.3: </span>Older versions of Python did not support <em>NULL</em> as the value for the
<em>methods</em> argument.</p>
</dd></dl>
<dl class="function">
<dt id="Py_InitModule4">
<a class="reference internal" href="structures.html#PyObject" title="PyObject">PyObject</a>* <tt class="descname">Py_InitModule4</tt><big>(</big>char<em> *name</em>, <a class="reference internal" href="structures.html#PyMethodDef" title="PyMethodDef">PyMethodDef</a><em> *methods</em>, char<em> *doc</em>, <a class="reference internal" href="structures.html#PyObject" title="PyObject">PyObject</a><em> *self</em>, int<em> apiver</em><big>)</big><a class="headerlink" href="#Py_InitModule4" title="Permalink to this definition">¶</a></dt>
<dd><em class="refcount">Return value: Borrowed reference.</em><p>Create a new module object based on a name and table of functions,
returning the new module object. If <em>doc</em> is non-<em>NULL</em>, it will be used
to define the docstring for the module. If <em>self</em> is non-<em>NULL</em>, it will
passed to the functions of the module as their (otherwise <em>NULL</em>) first
parameter. (This was added as an experimental feature, and there are no
known uses in the current version of Python.) For <em>apiver</em>, the only value
which should be passed is defined by the constant
<tt class="xref py py-const docutils literal"><span class="pre">PYTHON_API_VERSION</span></tt>.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">Most uses of this function should probably be using the
<a class="reference internal" href="#Py_InitModule3" title="Py_InitModule3"><tt class="xref c c-func docutils literal"><span class="pre">Py_InitModule3()</span></tt></a> instead; only use this if you are sure you need
it.</p>
</div>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.3: </span>Older versions of Python did not support <em>NULL</em> as the value for the
<em>methods</em> argument.</p>
</dd></dl>
<dl class="var">
<dt id="_Py_NoneStruct">
<a class="reference internal" href="structures.html#PyObject" title="PyObject">PyObject</a> <tt class="descname">_Py_NoneStruct</tt><a class="headerlink" href="#_Py_NoneStruct" title="Permalink to this definition">¶</a></dt>
<dd><p>Object which is visible in Python as <tt class="docutils literal"><span class="pre">None</span></tt>. This should only be
accessed using the <tt class="docutils literal"><span class="pre">Py_None</span></tt> macro, which evaluates to a pointer to this
object.</p>
</dd></dl>
</div>
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