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<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968" /><title>ioctl VIDIOC_SUBSCRIBE_EVENT, VIDIOC_UNSUBSCRIBE_EVENT</title><meta name="generator" content="DocBook XSL Stylesheets V1.76.1" /><link rel="home" href="index.html" title="LINUX MEDIA INFRASTRUCTURE API" /><link rel="up" href="user-func.html" title="Appendix A. Function Reference" /><link rel="prev" href="vidioc-streamon.html" title="ioctl VIDIOC_STREAMON, VIDIOC_STREAMOFF" /><link rel="next" href="func-mmap.html" title="V4L2 mmap()" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">ioctl VIDIOC_SUBSCRIBE_EVENT, VIDIOC_UNSUBSCRIBE_EVENT</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="vidioc-streamon.html">Prev</a> </td><th width="60%" align="center">Appendix A. Function Reference</th><td width="20%" align="right"> <a accesskey="n" href="func-mmap.html">Next</a></td></tr></table><hr /></div><div class="refentry" title="ioctl VIDIOC_SUBSCRIBE_EVENT, VIDIOC_UNSUBSCRIBE_EVENT"><a id="vidioc-subscribe-event"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>VIDIOC_SUBSCRIBE_EVENT, VIDIOC_UNSUBSCRIBE_EVENT — Subscribe or unsubscribe event</p></div><div class="refsynopsisdiv" title="Synopsis"><h2>Synopsis</h2><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">int <strong>fsfuncioctl</strong>(</code></td><td>int <var class="pdparam">fd</var>, </td></tr><tr><td> </td><td>int <var class="pdparam">request</var>, </td></tr><tr><td> </td><td>struct v4l2_event_subscription
*<var class="pdparam">argp</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1" title="Arguments"><a id="id3194355"></a><h2>Arguments</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>fd</code></em></span></dt><dd><p>File descriptor returned by <a class="link" href="func-open.html" title="V4L2 open()"><code class="function">open()</code></a>.</p></dd><dt><span class="term"><em class="parameter"><code>request</code></em></span></dt><dd><p>VIDIOC_SUBSCRIBE_EVENT, VIDIOC_UNSUBSCRIBE_EVENT</p></dd><dt><span class="term"><em class="parameter"><code>argp</code></em></span></dt><dd><p></p></dd></dl></div></div><div class="refsect1" title="Description"><a id="id3195396"></a><h2>Description</h2><p>Subscribe or unsubscribe V4L2 event. Subscribed events are
dequeued by using the <a class="link" href="vidioc-dqevent.html" title="ioctl VIDIOC_DQEVENT"><code class="constant">VIDIOC_DQEVENT</code></a> ioctl.</p><div class="table"><a id="v4l2-event-subscription"></a><p class="title"><strong>Table A.83. struct <span class="structname">v4l2_event_subscription</span></strong></p><div class="table-contents"><table summary="struct v4l2_event_subscription" width="100%" border="0"><colgroup><col class="c1" /><col class="c2" /><col class="c3" /></colgroup><tbody valign="top"><tr><td valign="top">__u32</td><td valign="top"><em class="structfield"><code>type</code></em></td><td valign="top">Type of the event.</td></tr><tr><td valign="top">__u32</td><td valign="top"><em class="structfield"><code>reserved</code></em>[7]</td><td valign="top">Reserved for future extensions. Drivers and applications
must set the array to zero.</td></tr></tbody></table></div></div><br class="table-break" /><div class="table"><a id="event-type"></a><p class="title"><strong>Table A.84. Event Types</strong></p><div class="table-contents"><table summary="Event Types" width="100%" border="0"><colgroup><col class="c1" /><col class="c2" /><col class="c3" /></colgroup><tbody valign="top"><tr><td valign="top"><code class="constant">V4L2_EVENT_ALL</code></td><td valign="top">0</td><td valign="top">All events. V4L2_EVENT_ALL is valid only for
VIDIOC_UNSUBSCRIBE_EVENT for unsubscribing all events at once.
</td></tr><tr><td valign="top"><code class="constant">V4L2_EVENT_VSYNC</code></td><td valign="top">1</td><td valign="top">This event is triggered on the vertical sync.
This event has struct <a class="link" href="vidioc-subscribe-event.html#v4l2-event-vsync" title="Table A.85. struct v4l2_event_vsync">v4l2_event_vsync</a> associated with it.
</td></tr><tr><td valign="top"><code class="constant">V4L2_EVENT_EOS</code></td><td valign="top">2</td><td valign="top">This event is triggered when the end of a stream is reached.
This is typically used with MPEG decoders to report to the application
when the last of the MPEG stream has been decoded.
</td></tr><tr><td valign="top"><code class="constant">V4L2_EVENT_PRIVATE_START</code></td><td valign="top">0x08000000</td><td valign="top">Base event number for driver-private events.</td></tr></tbody></table></div></div><br class="table-break" /><div class="table"><a id="v4l2-event-vsync"></a><p class="title"><strong>Table A.85. struct <span class="structname">v4l2_event_vsync</span></strong></p><div class="table-contents"><table summary="struct v4l2_event_vsync" width="100%" border="0"><colgroup><col class="c1" /><col class="c2" /><col class="c3" /></colgroup><tbody valign="top"><tr><td valign="top">__u8</td><td valign="top"><em class="structfield"><code>field</code></em></td><td valign="top">The upcoming field. See enum <a class="link" href="field-order.html#v4l2-field" title="Table 3.8. enum v4l2_field">v4l2_field</a>.</td></tr></tbody></table></div></div><br class="table-break" /></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="vidioc-streamon.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="user-func.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="func-mmap.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">ioctl VIDIOC_STREAMON, VIDIOC_STREAMOFF </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> V4L2 mmap()</td></tr></table></div></body></html>
