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Mauro Carvalho Chehab8e080c22009-09-13 22:16:04 -03001<refentry id="vidioc-g-input">
2 <refmeta>
3 <refentrytitle>ioctl VIDIOC_G_INPUT, VIDIOC_S_INPUT</refentrytitle>
4 &manvol;
5 </refmeta>
6
7 <refnamediv>
8 <refname>VIDIOC_G_INPUT</refname>
9 <refname>VIDIOC_S_INPUT</refname>
10 <refpurpose>Query or select the current video input</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_INPUT, VIDIOC_S_INPUT</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 input applications call the
53<constant>VIDIOC_G_INPUT</constant> ioctl with a pointer to an integer
54where the driver stores the number of the input, as in the
55&v4l2-input; <structfield>index</structfield> field. This ioctl will
56fail only when there are no video inputs, returning
57<errorcode>EINVAL</errorcode>.</para>
58
59 <para>To select a video input applications store the number of the
60desired input in an integer and call the
61<constant>VIDIOC_S_INPUT</constant> ioctl with a pointer to this
62integer. Side effects are possible. For example inputs may support
63different video standards, so the driver may implicitly switch the
64current standard. It is good practice to select an input before
65querying or negotiating any other parameters.</para>
66
67 <para>Information about video inputs is available using the
68&VIDIOC-ENUMINPUT; 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 input is out of bounds, or
79there are no video inputs at all and this ioctl is not
80supported.</para>
81 </listitem>
82 </varlistentry>
83 <varlistentry>
84 <term><errorcode>EBUSY</errorcode></term>
85 <listitem>
86 <para>I/O is in progress, the input cannot be
87switched.</para>
88 </listitem>
89 </varlistentry>
90 </variablelist>
91 </refsect1>
92</refentry>
93
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