1<html><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968"><title>media ioctl()</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1"><link rel="home" href="index.html" title="LINUX MEDIA INFRASTRUCTURE API"><link rel="up" href="media-user-func.html" title="Appendix&#160;L.&#160;Function Reference"><link rel="prev" href="media-func-close.html" title="media close()"><link rel="next" href="media-ioc-device-info.html" title="ioctl MEDIA_IOC_DEVICE_INFO"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">media ioctl()</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="media-func-close.html">Prev</a>&#160;</td><th width="60%" align="center">Appendix&#160;L.&#160;Function Reference</th><td width="20%" align="right">&#160;<a accesskey="n" href="media-ioc-device-info.html">Next</a></td></tr></table><hr></div><div class="refentry"><a name="media-func-ioctl"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>media-ioctl &#8212; Control a media device</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><div class="funcsynopsis"><pre class="funcsynopsisinfo">#include &lt;sys/ioctl.h&gt;</pre><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">ioctl</b>(</code></td><td>int <var class="pdparam">fd</var>, </td></tr><tr><td>&#160;</td><td>int <var class="pdparam">request</var>, </td></tr><tr><td>&#160;</td><td>void *<var class="pdparam">argp</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer">&#160;</div></div></div><div class="refsect1"><a name="idp1134058172"></a><h2>Arguments</h2><div class="variablelist"><dl class="variablelist"><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>Media ioctl request code as defined in the media.h header file,
2	  for example MEDIA_IOC_SETUP_LINK.</p></dd><dt><span class="term"><em class="parameter"><code>argp</code></em></span></dt><dd><p>Pointer to a request-specific structure.</p></dd></dl></div></div><div class="refsect1"><a name="idp1134101644"></a><h2>Description</h2><p>The <code class="function">ioctl()</code> function manipulates media device
3    parameters. The argument <em class="parameter"><code>fd</code></em> must be an open file
4    descriptor.</p><p>The ioctl <em class="parameter"><code>request</code></em> code specifies the media
5    function to be called. It has encoded in it whether the argument is an
6    input, output or read/write parameter, and the size of the argument
7    <em class="parameter"><code>argp</code></em> in bytes.</p><p>Macros and structures definitions specifying media ioctl requests and
8    their parameters are located in the media.h header file. All media ioctl
9    requests, their respective function and parameters are specified in
10    <a class="xref" href="media-user-func.html" title="Appendix&#160;L.&#160;Function Reference">Appendix&#160;L, <i>Function Reference</i></a>.</p></div><div class="refsect1"><a name="idp1134104988"></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. The generic error codes are described at the <a class="link" href="gen_errors.html#gen-errors" title="Table&#160;19.1.&#160;Generic error codes">Generic Error Codes</a> chapter.</p><p>Request-specific error codes are listed in the
11    individual requests descriptions.</p><p>When an ioctl that takes an output or read/write parameter fails,
12    the parameter remains unmodified.</p></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="media-func-close.html">Prev</a>&#160;</td><td width="20%" align="center"><a accesskey="u" href="media-user-func.html">Up</a></td><td width="40%" align="right">&#160;<a accesskey="n" href="media-ioc-device-info.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">media close()&#160;</td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top">&#160;ioctl MEDIA_IOC_DEVICE_INFO</td></tr></table></div></body></html>
13