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<refentry id="vidioc-overlay">
<refmeta>
<refentrytitle>ioctl VIDIOC_OVERLAY</refentrytitle>
&manvol;
</refmeta>
<refnamediv>
<refname>VIDIOC_OVERLAY</refname>
<refpurpose>Start or stop video overlay</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcprototype>
<funcdef>int <function>ioctl</function></funcdef>
<paramdef>int <parameter>fd</parameter></paramdef>
<paramdef>int <parameter>request</parameter></paramdef>
<paramdef>const int *<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>VIDIOC_OVERLAY</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>argp</parameter></term>
<listitem>
<para></para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>This ioctl is part of the <link linkend="overlay">video
overlay</link> I/O method. Applications call
<constant>VIDIOC_OVERLAY</constant> 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.</para>
<para>Drivers do not support &VIDIOC-STREAMON; or
&VIDIOC-STREAMOFF; with <constant>V4L2_BUF_TYPE_VIDEO_OVERLAY</constant>.</para>
</refsect1>
<refsect1>
&return-value;
<variablelist>
<varlistentry>
<term><errorcode>EINVAL</errorcode></term>
<listitem>
<para>The overlay parameters have not been set up. See <xref
linkend="overlay" /> for the necessary steps.</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
</refentry>