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Diffstat (limited to 'Documentation/DocBook/media/v4l/vidioc-g-output.xml')
-rw-r--r-- | Documentation/DocBook/media/v4l/vidioc-g-output.xml | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/Documentation/DocBook/media/v4l/vidioc-g-output.xml b/Documentation/DocBook/media/v4l/vidioc-g-output.xml new file mode 100644 index 00000000000..fd45f1c13cc --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-output.xml @@ -0,0 +1,84 @@ +<refentry id="vidioc-g-output"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_OUTPUT, VIDIOC_S_OUTPUT</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_OUTPUT</refname> + <refname>VIDIOC_S_OUTPUT</refname> + <refpurpose>Query or select the current video output</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_OUTPUT, VIDIOC_S_OUTPUT</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 output applications call the +<constant>VIDIOC_G_OUTPUT</constant> ioctl with a pointer to an integer +where the driver stores the number of the output, as in the +&v4l2-output; <structfield>index</structfield> field. This ioctl +will fail only when there are no video outputs, returning the +&EINVAL;.</para> + + <para>To select a video output applications store the number of the +desired output in an integer and call the +<constant>VIDIOC_S_OUTPUT</constant> ioctl with a pointer to this integer. +Side effects are possible. For example outputs may support different +video standards, so the driver may implicitly switch the current +standard. It is good practice to select an output before querying or +negotiating any other parameters.</para> + + <para>Information about video outputs is available using the +&VIDIOC-ENUMOUTPUT; ioctl.</para> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The number of the video output is out of bounds, or +there are no video outputs at all.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> |