Based on kernel version 3.0.4. Page generated on 2011-10-03 22:07 EST.
1 <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 54 where the driver stores the number of the input, as in the 55 &v4l2-input; <structfield>index</structfield> field. This ioctl will 56 fail 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 60 desired input in an integer and call the 61 <constant>VIDIOC_S_INPUT</constant> ioctl with a pointer to this 62 integer. Side effects are possible. For example inputs may support 63 different video standards, so the driver may implicitly switch the 64 current standard. It is good practice to select an input before 65 querying 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 79 there are no video inputs 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 input 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 -->
