1<refentry id="vidioc-overlay">
2  <refmeta>
3    <refentrytitle>ioctl VIDIOC_OVERLAY</refentrytitle>
4    &manvol;
5  </refmeta>
6
7  <refnamediv>
8    <refname>VIDIOC_OVERLAY</refname>
9    <refpurpose>Start or stop video overlay</refpurpose>
10  </refnamediv>
11
12  <refsynopsisdiv>
13    <funcsynopsis>
14      <funcprototype>
15	<funcdef>int <function>ioctl</function></funcdef>
16	<paramdef>int <parameter>fd</parameter></paramdef>
17	<paramdef>int <parameter>request</parameter></paramdef>
18	<paramdef>const int *<parameter>argp</parameter></paramdef>
19      </funcprototype>
20    </funcsynopsis>
21  </refsynopsisdiv>
22
23  <refsect1>
24    <title>Arguments</title>
25
26    <variablelist>
27      <varlistentry>
28	<term><parameter>fd</parameter></term>
29	<listitem>
30	  <para>&fd;</para>
31	</listitem>
32      </varlistentry>
33      <varlistentry>
34	<term><parameter>request</parameter></term>
35	<listitem>
36	  <para>VIDIOC_OVERLAY</para>
37	</listitem>
38      </varlistentry>
39      <varlistentry>
40	<term><parameter>argp</parameter></term>
41	<listitem>
42	  <para></para>
43	</listitem>
44      </varlistentry>
45    </variablelist>
46  </refsect1>
47
48  <refsect1>
49    <title>Description</title>
50
51    <para>This ioctl is part of the <link linkend="overlay">video
52    overlay</link> I/O method. Applications call
53    <constant>VIDIOC_OVERLAY</constant> to start or stop the
54    overlay. It takes a pointer to an integer which must be set to
55    zero by the application to stop overlay, to one to start.</para>
56
57    <para>Drivers do not support &VIDIOC-STREAMON; or
58&VIDIOC-STREAMOFF; with <constant>V4L2_BUF_TYPE_VIDEO_OVERLAY</constant>.</para>
59  </refsect1>
60
61  <refsect1>
62    &return-value;
63
64    <variablelist>
65      <varlistentry>
66	<term><errorcode>EINVAL</errorcode></term>
67	<listitem>
68	  <para>The overlay parameters have not been set up. See <xref
69linkend="overlay" /> for the necessary steps.</para>
70	</listitem>
71      </varlistentry>
72    </variablelist>
73  </refsect1>
74</refentry>
75