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+<refentry id="media-func-ioctl">
+  <refmeta>
+    <refentrytitle>media ioctl()</refentrytitle>
+    &manvol;
+  </refmeta>
+
+  <refnamediv>
+    <refname>media-ioctl</refname>
+    <refpurpose>Control a media device</refpurpose>
+  </refnamediv>
+
+  <refsynopsisdiv>
+    <funcsynopsis>
+      <funcsynopsisinfo>#include &lt;sys/ioctl.h&gt;</funcsynopsisinfo>
+      <funcprototype>
+	<funcdef>int <function>ioctl</function></funcdef>
+	<paramdef>int <parameter>fd</parameter></paramdef>
+	<paramdef>int <parameter>request</parameter></paramdef>
+	<paramdef>void *<parameter>argp</parameter></paramdef>
+      </funcprototype>
+    </funcsynopsis>
+  </refsynopsisdiv>
+
+  <refsect1>
+    <title>Arguments</title>
+
+    <variablelist>
+      <varlistentry>
+	<term><parameter>fd</parameter></term>
+	<listitem>
+	  <para>&fd;</para>
+	</listitem>
+      </varlistentry>
+      <varlistentry>
+	<term><parameter>request</parameter></term>
+	<listitem>
+	  <para>Media ioctl request code as defined in the media.h header file,
+	  for example MEDIA_IOC_SETUP_LINK.</para>
+	</listitem>
+      </varlistentry>
+      <varlistentry>
+	<term><parameter>argp</parameter></term>
+	<listitem>
+	  <para>Pointer to a request-specific structure.</para>
+	</listitem>
+      </varlistentry>
+    </variablelist>
+  </refsect1>
+
+  <refsect1>
+    <title>Description</title>
+    <para>The <function>ioctl()</function> function manipulates media device
+    parameters. The argument <parameter>fd</parameter> must be an open file
+    descriptor.</para>
+    <para>The ioctl <parameter>request</parameter> code specifies the media
+    function to be called. It has encoded in it whether the argument is an
+    input, output or read/write parameter, and the size of the argument
+    <parameter>argp</parameter> in bytes.</para>
+    <para>Macros and structures definitions specifying media ioctl requests and
+    their parameters are located in the media.h header file. All media ioctl
+    requests, their respective function and parameters are specified in
+    <xref linkend="media-user-func" />.</para>
+  </refsect1>
+
+  <refsect1>
+    <title>Return Value</title>
+
+    <para><function>ioctl()</function> returns <returnvalue>0</returnvalue> on
+    success. On failure, <returnvalue>-1</returnvalue> is returned, and the
+    <varname>errno</varname> variable is set appropriately. Generic error codes
+    are listed below, and request-specific error codes are listed in the
+    individual requests descriptions.</para>
+    <para>When an ioctl that takes an output or read/write parameter fails,
+    the parameter remains unmodified.</para>
+
+    <variablelist>
+      <varlistentry>
+	<term><errorcode>EBADF</errorcode></term>
+	<listitem>
+	  <para><parameter>fd</parameter> is not a valid open file descriptor.
+	  </para>
+	</listitem>
+      </varlistentry>
+      <varlistentry>
+	<term><errorcode>EFAULT</errorcode></term>
+	<listitem>
+	  <para><parameter>argp</parameter> references an inaccessible memory
+	  area.</para>
+	</listitem>
+      </varlistentry>
+      <varlistentry>
+	<term><errorcode>EINVAL</errorcode></term>
+	<listitem>
+	  <para>The <parameter>request</parameter> or the data pointed to by
+	  <parameter>argp</parameter> is not valid. This is a very common error
+	  code, see the individual ioctl requests listed in
+	  <xref linkend="media-user-func" /> for actual causes.</para>
+	</listitem>
+      </varlistentry>
+      <varlistentry>
+	<term><errorcode>ENOMEM</errorcode></term>
+	<listitem>
+	  <para>Insufficient kernel memory was available to complete the
+	  request.</para>
+	</listitem>
+      </varlistentry>
+      <varlistentry>
+	<term><errorcode>ENOTTY</errorcode></term>
+	<listitem>
+	  <para><parameter>fd</parameter> is  not  associated  with  a character
+	  special device.</para>
+	</listitem>
+      </varlistentry>
+    </variablelist>
+  </refsect1>
+</refentry>