linux/Documentation/linux_tv/media/v4l/vidioc-enumaudio.rst
Mauro Carvalho Chehab cdb4af0fd5 doc-rst: linux_tv: Error codes should be const
All error codes should be const. Most are, but there are
lots of places where we forgot to add <constant> at the DocBook.

Fix those via this small script:
	for i in $(git grep -lE "\s+E[A-Z]+\b" Documentation/linux_tv/); do perl -ne 's,([^\`])\b(E[A-Z]+)\b,\1``\2``,g; print $_' <$i >a && mv a $i; done

As there are false positives, we needed to merge only the changes
that make sense, skipping the c blocks and skipping things like
EDID, EN, ETS that were also converted by the above code.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2016-07-03 12:06:32 -03:00

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.. -*- coding: utf-8; mode: rst -*-
.. _VIDIOC_ENUMAUDIO:
**********************
ioctl VIDIOC_ENUMAUDIO
**********************
*man VIDIOC_ENUMAUDIO(2)*
Enumerate audio inputs
Synopsis
========
.. cpp:function:: int ioctl( int fd, int request, struct v4l2_audio *argp )
Arguments
=========
``fd``
File descriptor returned by :ref:`open() <func-open>`.
``request``
VIDIOC_ENUMAUDIO
``argp``
Description
===========
To query the attributes of an audio input applications initialize the
``index`` field and zero out the ``reserved`` array of a struct
:ref:`v4l2_audio <v4l2-audio>` and call the :ref:`VIDIOC_ENUMAUDIO`
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 inputs applications shall begin at index
zero, incrementing by one until the driver returns ``EINVAL``.
See :ref:`VIDIOC_G_AUDIO <VIDIOC_G_AUDIO>` for a description of struct
:ref:`v4l2_audio <v4l2-audio>`.
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 input is out of bounds.
.. ------------------------------------------------------------------------------
.. This file was automatically converted from DocBook-XML with the dbxml
.. library (https://github.com/return42/sphkerneldoc). The origin XML comes
.. from the linux kernel, refer to:
..
.. * https://github.com/torvalds/linux/tree/master/Documentation/DocBook
.. ------------------------------------------------------------------------------