e8be7e97e6
instead of declaring the uAPI structs using usual refs, e. g.: .. _foo-struct: Use the C domain way: .. c:type:: foo_struct This way, the kAPI documentation can use cross-references to point to the uAPI symbols. That solves about ~100 undefined warnings like: WARNING: c:type reference target not found: foo_struct Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
66 lines
1.8 KiB
ReStructuredText
66 lines
1.8 KiB
ReStructuredText
.. -*- coding: utf-8; mode: rst -*-
|
|
|
|
.. _VIDIOC_G_OUTPUT:
|
|
|
|
**************************************
|
|
ioctl VIDIOC_G_OUTPUT, VIDIOC_S_OUTPUT
|
|
**************************************
|
|
|
|
Name
|
|
====
|
|
|
|
VIDIOC_G_OUTPUT - VIDIOC_S_OUTPUT - Query or select the current video output
|
|
|
|
|
|
Synopsis
|
|
========
|
|
|
|
.. c:function:: int ioctl( int fd, VIDIOC_G_OUTPUT, int *argp )
|
|
:name: VIDIOC_G_OUTPUT
|
|
|
|
.. c:function:: int ioctl( int fd, VIDIOC_S_OUTPUT, int *argp )
|
|
:name: VIDIOC_S_OUTPUT
|
|
|
|
|
|
Arguments
|
|
=========
|
|
|
|
``fd``
|
|
File descriptor returned by :ref:`open() <func-open>`.
|
|
|
|
``argp``
|
|
|
|
|
|
Description
|
|
===========
|
|
|
|
To query the current video output applications call the
|
|
:ref:`VIDIOC_G_OUTPUT <VIDIOC_G_OUTPUT>` ioctl with a pointer to an integer where the driver
|
|
stores the number of the output, as in the struct
|
|
:c:type:`v4l2_output` ``index`` field. This ioctl will
|
|
fail only when there are no video outputs, returning the ``EINVAL`` error
|
|
code.
|
|
|
|
To select a video output applications store the number of the desired
|
|
output in an integer and call the :ref:`VIDIOC_S_OUTPUT <VIDIOC_G_OUTPUT>` 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. standard. Because of these possible side
|
|
effects applications must select an output before querying or
|
|
negotiating any other parameters.
|
|
|
|
Information about video outputs is available using the
|
|
:ref:`VIDIOC_ENUMOUTPUT` ioctl.
|
|
|
|
|
|
Return Value
|
|
============
|
|
|
|
On success 0 is returned, on error -1 and the ``errno`` variable is set
|
|
appropriately. The generic error codes are described at the
|
|
:ref:`Generic Error Codes <gen-errors>` chapter.
|
|
|
|
EINVAL
|
|
The number of the video output is out of bounds, or there are no
|
|
video outputs at all.
|