You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
sip4-tqt/doc/html/embedding.html

162 lines
7.5 KiB

<!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>Using the C API when Embedding &mdash; SIP 4.10.5 Reference Guide</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: '4.10.5',
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="top" title="SIP 4.10.5 Reference Guide" href="index.html" />
<link rel="next" title="Python API for Applications" href="python_api.html" />
<link rel="prev" title="C API for Handwritten Code" href="c_api.html" />
</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="python_api.html" title="Python API for Applications"
accesskey="N">next</a> |</li>
<li class="right" >
<a href="c_api.html" title="C API for Handwritten Code"
accesskey="P">previous</a> |</li>
<li><a href="index.html">SIP 4.10.5 Reference Guide</a> &raquo;</li>
</ul>
</div>
<div class="document">
<div class="documentwrapper">
<div class="bodywrapper">
<div class="body">
<div class="section" id="using-the-c-api-when-embedding">
<h1>Using the C API when Embedding<a class="headerlink" href="#using-the-c-api-when-embedding" title="Permalink to this headline"></a></h1>
<p>The <a class="reference external" href="c_api.html#ref-c-api"><em>C API</em></a> is intended to be called from handwritten code in
SIP generated modules. However it is also often necessary to call it from C or
C++ applications that embed the Python interpreter and need to pass C or C++
instances between the application and the interpreter.</p>
<p>The API is exported by the SIP module as a <tt class="docutils literal"><span class="pre">sipAPIDef</span></tt> data structure
containing a set of function pointers. The data structure is defined in the
SIP header file <tt class="docutils literal"><span class="pre">sip.h</span></tt>. The data structure is wrapped as a Python
<tt class="docutils literal"><span class="pre">PyCObject</span></tt> object and is referenced by the name <tt class="docutils literal"><span class="pre">_C_API</span></tt> in the SIP
module dictionary.</p>
<p>Each member of the data structure is a pointer to one of the functions of the
SIP API. The name of the member can be derived from the function name by
replacing the <tt class="docutils literal"><span class="pre">sip</span></tt> prefix with <tt class="docutils literal"><span class="pre">api</span></tt> and converting each word in the
name to lower case and preceding it with an underscore. For example:</p>
<blockquote>
<p><tt class="docutils literal"><span class="pre">sipExportSymbol</span></tt> becomes <tt class="docutils literal"><span class="pre">api_export_symbol</span></tt></p>
<p><tt class="docutils literal"><span class="pre">sipWrapperCheck</span></tt> becomes <tt class="docutils literal"><span class="pre">api_wrapper_check</span></tt></p>
</blockquote>
<p>Note that the type objects that SIP generates for a wrapped module (see
<a class="reference external" href="c_api.html#ref-type-structures"><em>Generated Type Structures</em></a>, <a class="reference external" href="c_api.html#ref-enum-type-objects"><em>Generated Named Enum Type Objects</em></a> and
<a class="reference external" href="c_api.html#ref-exception-objects"><em>Generated Exception Objects</em></a>) cannot be refered to directly and must be
obtained using the <a title="sipFindType" class="reference external" href="c_api.html#sipFindType"><tt class="xref docutils literal"><span class="pre">sipFindType()</span></tt></a> function. Of course, the
corresponding modules must already have been imported into the interpreter.</p>
<p>The following code fragment shows how to get a pointer to the <tt class="docutils literal"><span class="pre">sipAPIDef</span></tt>
data structure:</p>
<div class="highlight-python"><pre>#include &lt;sip.h&gt;
const sipAPIDef *get_sip_api()
{
PyObject *sip_module;
PyObject *sip_module_dict;
PyObject *c_api;
/* Import the SIP module. */
sip_module = PyImport_ImportModule("sip");
if (sip_module == NULL)
return NULL;
/* Get the module's dictionary. */
sip_module_dict = PyModule_GetDict(sip_module);
/* Get the "_C_API" attribute. */
c_api = PyDict_GetItemString(sip_module_dict, "_C_API");
if (c_api == NULL)
return NULL;
/* Sanity check that it is the right type. */
if (!PyCObject_Check(c_api))
return NULL;
/* Get the actual pointer from the object. */
return (const sipAPIDef *)PyCObject_AsVoidPtr(c_api);
}</pre>
</div>
</div>
</div>
</div>
</div>
<div class="sphinxsidebar">
<div class="sphinxsidebarwrapper">
<h4>Previous topic</h4>
<p class="topless"><a href="c_api.html"
title="previous chapter">C API for Handwritten Code</a></p>
<h4>Next topic</h4>
<p class="topless"><a href="python_api.html"
title="next chapter">Python API for Applications</a></p>
<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="python_api.html" title="Python API for Applications"
>next</a> |</li>
<li class="right" >
<a href="c_api.html" title="C API for Handwritten Code"
>previous</a> |</li>
<li><a href="index.html">SIP 4.10.5 Reference Guide</a> &raquo;</li>
</ul>
</div>
<div class="footer">
&copy; Copyright 2010 Riverbank Computing Limited.
Created using <a href="http://sphinx.pocoo.org/">Sphinx</a> 0.6.4.
</div>
</body>
</html>