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Based on kernel version 3.0.4. Page generated on 2011-10-03 22:07 EST.

1	<refentry id="vidioc-g-output">
2	  <refmeta>
3	    <refentrytitle>ioctl VIDIOC_G_OUTPUT, VIDIOC_S_OUTPUT</refentrytitle>
4	    &manvol;
5	  </refmeta>
6	
7	  <refnamediv>
8	    <refname>VIDIOC_G_OUTPUT</refname>
9	    <refname>VIDIOC_S_OUTPUT</refname>
10	    <refpurpose>Query or select the current video output</refpurpose>
11	  </refnamediv>
12	
13	  <refsynopsisdiv>
14	    <funcsynopsis>
15	      <funcprototype>
16		<funcdef>int <function>ioctl</function></funcdef>
17		<paramdef>int <parameter>fd</parameter></paramdef>
18		<paramdef>int <parameter>request</parameter></paramdef>
19		<paramdef>int *<parameter>argp</parameter></paramdef>
20	      </funcprototype>
21	    </funcsynopsis>
22	  </refsynopsisdiv>
23	
24	  <refsect1>
25	    <title>Arguments</title>
26	
27	    <variablelist>
28	      <varlistentry>
29		<term><parameter>fd</parameter></term>
30		<listitem>
31		  <para>&fd;</para>
32		</listitem>
33	      </varlistentry>
34	      <varlistentry>
35		<term><parameter>request</parameter></term>
36		<listitem>
37		  <para>VIDIOC_G_OUTPUT, VIDIOC_S_OUTPUT</para>
38		</listitem>
39	      </varlistentry>
40	      <varlistentry>
41		<term><parameter>argp</parameter></term>
42		<listitem>
43		  <para></para>
44		</listitem>
45	      </varlistentry>
46	    </variablelist>
47	  </refsect1>
48	
49	  <refsect1>
50	    <title>Description</title>
51	
52	    <para>To query the current video output applications call the
53	<constant>VIDIOC_G_OUTPUT</constant> ioctl with a pointer to an integer
54	where the driver stores the number of the output, as in the
55	&v4l2-output; <structfield>index</structfield> field. This ioctl
56	will fail only when there are no video outputs, returning the
57	&EINVAL;.</para>
58	
59	    <para>To select a video output applications store the number of the
60	desired output in an integer and call the
61	<constant>VIDIOC_S_OUTPUT</constant> ioctl with a pointer to this integer.
62	Side effects are possible. For example outputs may support different
63	video standards, so the driver may implicitly switch the current
64	standard. It is good practice to select an output before querying or
65	negotiating any other parameters.</para>
66	
67	    <para>Information about video outputs is available using the
68	&VIDIOC-ENUMOUTPUT; ioctl.</para>
69	  </refsect1>
70	
71	  <refsect1>
72	    &return-value;
73	
74	    <variablelist>
75	      <varlistentry>
76		<term><errorcode>EINVAL</errorcode></term>
77		<listitem>
78		  <para>The number of the video output is out of bounds, or
79	there are no video outputs at all and this ioctl is not
80	supported.</para>
81		</listitem>
82	      </varlistentry>
83	      <varlistentry>
84		<term><errorcode>EBUSY</errorcode></term>
85		<listitem>
86		  <para>I/O is in progress, the output cannot be
87	switched.</para>
88		</listitem>
89	      </varlistentry>
90	    </variablelist>
91	  </refsect1>
92	</refentry>
93	
94	<!--
95	Local Variables:
96	mode: sgml
97	sgml-parent-document: "v4l2.sgml"
98	indent-tabs-mode: nil
99	End:
100	-->
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