101 lines
2.7 KiB
XML
101 lines
2.7 KiB
XML
<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 and this ioctl is not
|
|
supported.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><errorcode>EBUSY</errorcode></term>
|
|
<listitem>
|
|
<para>I/O is in progress, the output cannot be
|
|
switched.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
</refsect1>
|
|
</refentry>
|
|
|
|
<!--
|
|
Local Variables:
|
|
mode: sgml
|
|
sgml-parent-document: "v4l2.sgml"
|
|
indent-tabs-mode: nil
|
|
End:
|
|
-->
|