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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_OVERLAY</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2" /><link rel="home" href="index.html" title="LINUX MEDIA INFRASTRUCTURE API" /><link rel="up" href="apa.html" title="Appendix A. Function Reference" /><link rel="prev" href="re52.html" title="ioctl VIDIOC_LOG_STATUS" /><link rel="next" href="re54.html" title="ioctl VIDIOC_QBUF, VIDIOC_DQBUF" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">ioctl VIDIOC_OVERLAY</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="re52.html">Prev</a> </td><th width="60%" align="center">Appendix A. Function Reference</th><td width="20%" align="right"> <a accesskey="n" href="re54.html">Next</a></td></tr></table><hr /></div><div class="refentry" title="ioctl VIDIOC_OVERLAY"><a id="vidioc-overlay"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>VIDIOC_OVERLAY — Start or stop video overlay</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 <b class="fsfunc">ioctl</b>(</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>const int *<var class="pdparam">argp</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1" title="Arguments"><a id="id2728074"></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="re64.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_OVERLAY</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="id2728142"></a><h2>Description</h2><p>This ioctl is part of the <a class="link" href="ch04s02.html" title="Video Overlay Interface">video
overlay</a> I/O method. Applications call
<code class="constant">VIDIOC_OVERLAY</code> to start or stop the
overlay. It takes a pointer to an integer which must be set to
zero by the application to stop overlay, to one to start.</p><p>Drivers do not support <a class="link" href="re61.html" title="ioctl VIDIOC_STREAMON, VIDIOC_STREAMOFF"><code class="constant">VIDIOC_STREAMON</code></a> or
<a class="link" href="re61.html" title="ioctl VIDIOC_STREAMON, VIDIOC_STREAMOFF"><code class="constant">VIDIOC_STREAMOFF</code></a> with <code class="constant">V4L2_BUF_TYPE_VIDEO_OVERLAY</code>.</p></div><div class="refsect1" title="Return Value"><a id="id2728723"></a><h2>Return Value</h2><p>On success <span class="returnvalue">0</span> is returned, on error <span class="returnvalue">-1</span> and the <code class="varname">errno</code> variable is set appropriately:</p><div class="variablelist"><dl><dt><span class="term"><span class="errorcode">EINVAL</span></span></dt><dd><p>Video overlay is not supported, or the
parameters have not been set up. See <a class="xref" href="ch04s02.html" title="Video Overlay Interface">the section called “Video Overlay Interface”</a> for the necessary steps.</p></dd></dl></div></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="re52.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="apa.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="re54.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">ioctl VIDIOC_LOG_STATUS </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> ioctl VIDIOC_QBUF, VIDIOC_DQBUF</td></tr></table></div></body></html>
