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8e080c2e MCC |
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 | --> |