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+<refentry id="func-ioctl">
+ <refmeta>
+ <refentrytitle>V4L2 ioctl()</refentrytitle>
+ &manvol;
+ </refmeta>
+
+ <refnamediv>
+ <refname>v4l2-ioctl</refname>
+ <refpurpose>Program a V4L2 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>V4L2 ioctl request code as defined in the <filename>videodev2.h</filename> header file, for example
+VIDIOC_QUERYCAP.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><parameter>argp</parameter></term>
+ <listitem>
+ <para>Pointer to a function parameter, usually a structure.</para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>Description</title>
+
+ <para>The <function>ioctl()</function> function is used to program
+V4L2 devices. The argument <parameter>fd</parameter> must be an open
+file descriptor. An ioctl <parameter>request</parameter> 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. Macros and defines specifying V4L2 ioctl requests are located
+in the <filename>videodev2.h</filename> header file.
+Applications should use their own copy, not include the version in the
+kernel sources on the system they compile on. All V4L2 ioctl requests,
+their respective function and parameters are specified in <xref
+ linkend="user-func" />.</para>
+ </refsect1>
+
+ <refsect1>
+ &return-value;
+ <para>When an ioctl that takes an output or read/write parameter fails,
+ the parameter remains unmodified.</para>
+ </refsect1>
+</refentry>
+
+<!--
+Local Variables:
+mode: sgml
+sgml-parent-document: "v4l2.sgml"
+indent-tabs-mode: nil
+End:
+-->