gstreamer/docs/manual/links-api.xml

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<chapter id="chapter-links-api">
<title>Linking elements</title>
<sect1 id="section-link-basic">
<title>Making simple links</title>
<para>
You can link two pads with:
</para>
<programlisting>
GstPad *srcpad, *sinkpad;
srcpad = gst_element_get_pad (element1, "src");
sinpad = gst_element_get_pad (element2, "sink");
// link them
gst_pad_link (srcpad, sinkpad);
....
// and unlink them
gst_pad_unlink (srcpad, sinkpad);
</programlisting>
<para>
A convenient shortcut for the above code is done with the gst_element_link_pads ()
function:
</para>
<programlisting>
// link them
gst_element_link_pads (element1, "src", element2, "sink");
....
// and unlink them
gst_element_unlink_pads (element1, "src", element2, "sink");
</programlisting>
<para>
An even more convenient shortcut but only works for single-source, single-sink elements is the
gst_element_link () function:
</para>
<programlisting>
// link them
gst_element_link (element1, element2);
....
// and unlink them
gst_element_unlink (element1, element2);
</programlisting>
<para>
If you have more than one element to link, the gst_element_link_many () function takes
a NULL-terminated list of elements. Again this only works for single-source single-sink
elements:
</para>
<programlisting>
// link them
gst_element_link_many (element1, element2, element3, element4, NULL);
....
// and unlink them
gst_element_unlink_many (element1, element2, element3, element4, NULL);
</programlisting>
<para>
You can query if a pad is linked with
<function>GST_PAD_IS_LINKED (pad)</function>.
</para>
<para>
To query for the <ulink type="http"
url="../../gstreamer/html/GstPad.html"><classname>GstPad</classname></ulink>
a pad is linked to, use <function>gst_pad_get_peer (pad)</function>.
</para>
</sect1>
<sect1 id="section-link-filtered">
<title>Making filtered links</title>
<para>
You can also force a specific media type on the link by using
<function>gst_pad_link_filtered ()</function>
and <function>gst_element_link_filtered ()</function> with capabilities.
See <xref linkend="section-caps"/> for
an explanation of capabilities.
</para>
</sect1>
</chapter>