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- <refentry id="vidioc-g-input">
- <refmeta>
- <refentrytitle>ioctl VIDIOC_G_INPUT, VIDIOC_S_INPUT</refentrytitle>
- &manvol;
- </refmeta>
- <refnamediv>
- <refname>VIDIOC_G_INPUT</refname>
- <refname>VIDIOC_S_INPUT</refname>
- <refpurpose>Query or select the current video input</refpurpose>
- </refnamediv>
- <refsynopsisdiv>
- <funcsynopsis>
- <funcprototype>
- <funcdef>int <function>ioctl</function></funcdef>
- <paramdef>int <parameter>fd</parameter></paramdef>
- <paramdef>int <parameter>request</parameter></paramdef>
- <paramdef>int *<parameter>argp</parameter></paramdef>
- </funcprototype>
- </funcsynopsis>
- </refsynopsisdiv>
- <refsect1>
- <title>Arguments</title>
- <variablelist>
- <varlistentry>
- <term><parameter>fd</parameter></term>
- <listitem>
- <para>&fd;</para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term><parameter>request</parameter></term>
- <listitem>
- <para>VIDIOC_G_INPUT, VIDIOC_S_INPUT</para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term><parameter>argp</parameter></term>
- <listitem>
- <para></para>
- </listitem>
- </varlistentry>
- </variablelist>
- </refsect1>
- <refsect1>
- <title>Description</title>
- <para>To query the current video input applications call the
- <constant>VIDIOC_G_INPUT</constant> ioctl with a pointer to an integer
- where the driver stores the number of the input, as in the
- &v4l2-input; <structfield>index</structfield> field. This ioctl will
- fail only when there are no video inputs, returning
- <errorcode>EINVAL</errorcode>.</para>
- <para>To select a video input applications store the number of the
- desired input in an integer and call the
- <constant>VIDIOC_S_INPUT</constant> ioctl with a pointer to this
- integer. Side effects are possible. For example inputs may support
- different video standards, so the driver may implicitly switch the
- current standard. Because of these possible side effects applications
- must select an input before querying or negotiating any other parameters.</para>
- <para>Information about video inputs is available using the
- &VIDIOC-ENUMINPUT; ioctl.</para>
- </refsect1>
- <refsect1>
- &return-value;
- <variablelist>
- <varlistentry>
- <term><errorcode>EINVAL</errorcode></term>
- <listitem>
- <para>The number of the video input is out of bounds.</para>
- </listitem>
- </varlistentry>
- </variablelist>
- </refsect1>
- </refentry>
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