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<H2><A NAME="SECTION009590000000000000000"></A><A NAME="cObjects"></A>
<BR>
7.5.9 CObjects
</H2>

<P>
<a id='l2h-725' xml:id='l2h-725'></a>Refer to <em>Extending and Embedding the Python Interpreter</em>,
section&nbsp;1.12, ``Providing a C API for an Extension Module,'' for more
information on using these objects.

<P>
<dl><dt><b><tt class="ctype"><a id='l2h-726' xml:id='l2h-726'>PyCObject</a></tt></b></dt>
<dd>
  This subtype of <tt class="ctype">PyObject</tt> represents an opaque value, useful
  for C extension modules who need to pass an opaque value (as a
  <tt class="ctype">void*</tt> pointer) through Python code to other C code.  It is
  often used to make a C function pointer defined in one module
  available to other modules, so the regular import mechanism can be
  used to access C APIs defined in dynamically loaded modules.
</dl>

<P>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"><td><nobr>int&nbsp;<b><tt id='l2h-727' xml:id='l2h-727' class="cfunction">PyCObject_Check</tt></b>(</nobr></td><td>PyObject *<var>p</var>)</td></tr></table></dt>
<dd>
  Return true if its argument is a <tt class="ctype">PyCObject</tt>.
</dd></dl>

<P>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"><td><nobr>PyObject*&nbsp;<b><tt id='l2h-728' xml:id='l2h-728' class="cfunction">PyCObject_FromVoidPtr</tt></b>(</nobr></td><td>void* <var>cobj</var>,
                                                    void (*destr)(void *))</td></tr></table></dt>
<dd>
<div class="refcount-info">
  <span class="label">Return value:</span>
  <span class="value">New reference.</span>
</div>
  Create a <tt class="ctype">PyCObject</tt> from the <code>void *</code><var>cobj</var>.  The
  <var>destr</var> function will be called when the object is reclaimed,
  unless it is <tt class="constant">NULL</tt>.
</dd></dl>

<P>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"><td><nobr>PyObject*&nbsp;<b><tt id='l2h-729' xml:id='l2h-729' class="cfunction">PyCObject_FromVoidPtrAndDesc</tt></b>(</nobr></td><td>void* <var>cobj</var>,
                                  void* <var>desc</var>, void (*destr)(void *, void *))</td></tr></table></dt>
<dd>
<div class="refcount-info">
  <span class="label">Return value:</span>
  <span class="value">New reference.</span>
</div>
  Create a <tt class="ctype">PyCObject</tt> from the <tt class="ctype">void *</tt><var>cobj</var>.  The
  <var>destr</var> function will be called when the object is reclaimed.
  The <var>desc</var> argument can be used to pass extra callback data for
  the destructor function.
</dd></dl>

<P>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"><td><nobr>void*&nbsp;<b><tt id='l2h-730' xml:id='l2h-730' class="cfunction">PyCObject_AsVoidPtr</tt></b>(</nobr></td><td>PyObject* <var>self</var>)</td></tr></table></dt>
<dd>
  Return the object <tt class="ctype">void *</tt> that the <tt class="ctype">PyCObject</tt>
  <var>self</var> was created with.
</dd></dl>

<P>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"><td><nobr>void*&nbsp;<b><tt id='l2h-731' xml:id='l2h-731' class="cfunction">PyCObject_GetDesc</tt></b>(</nobr></td><td>PyObject* <var>self</var>)</td></tr></table></dt>
<dd>
  Return the description <tt class="ctype">void *</tt> that the <tt class="ctype">PyCObject</tt>
  <var>self</var> was created with.
</dd></dl>

<P>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"><td><nobr>int&nbsp;<b><tt id='l2h-732' xml:id='l2h-732' class="cfunction">PyCObject_SetVoidPtr</tt></b>(</nobr></td><td>PyObject* <var>self</var>, void* <var>cobj</var>)</td></tr></table></dt>
<dd>
  Set the void pointer inside <var>self</var> to <var>cobj</var>.
  The <tt class="ctype">PyCObject</tt> must not have an associated destructor.
  Return true on success, false on failure.
</dd></dl>

<P>

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<span class="release-info">Release 2.4.2, documentation updated on 28 September 2005.</span>
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