linux/Documentation/linux_tv/media/v4l/vidioc-enumaudioout.rst
Mauro Carvalho Chehab 64e4954619 doc-rst: linux_tv: remove trailing comments
The conversion script added some comments at the end.
They point to the original DocBook files, with will be
removed after the manual fixes. So, they'll be pointing
to nowere. So, remove those comments.

They'll be forever stored at the Kernel tree. So, if
someone wants the references, it is just a matter of
looking at the backlog.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2016-07-03 17:47:40 -03:00

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.. -*- coding: utf-8; mode: rst -*-
.. _VIDIOC_ENUMAUDIOOUT:
***********************
ioctl VIDIOC_ENUMAUDOUT
***********************
*man VIDIOC_ENUMAUDOUT(2)*
Enumerate audio outputs
Synopsis
========
.. cpp:function:: int ioctl( int fd, int request, struct v4l2_audioout *argp )
Arguments
=========
``fd``
File descriptor returned by :ref:`open() <func-open>`.
``request``
VIDIOC_ENUMAUDOUT
``argp``
Description
===========
To query the attributes of an audio output applications initialize the
``index`` field and zero out the ``reserved`` array of a struct
:ref:`v4l2_audioout <v4l2-audioout>` and call the ``VIDIOC_G_AUDOUT``
ioctl with a pointer to this structure. Drivers fill the rest of the
structure or return an ``EINVAL`` error code when the index is out of
bounds. To enumerate all audio outputs applications shall begin at index
zero, incrementing by one until the driver returns ``EINVAL``.
Note connectors on a TV card to loop back the received audio signal to a
sound card are not audio outputs in this sense.
See :ref:`VIDIOC_G_AUDIOout <VIDIOC_G_AUDIOout>` for a description of struct
:ref:`v4l2_audioout <v4l2-audioout>`.
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 audio output is out of bounds.