[deliverable/linux.git] / Documentation / linux_tv / media / v4l / vidioc-enumaudioout.rst

.. -*- 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.
Commit	Line	Data
	1	.. -- coding: utf-8; mode: rst --
	2
	3	.. _VIDIOC_ENUMAUDIOOUT:
	4
	5	***********************
	6	ioctl VIDIOC_ENUMAUDOUT
	7	***********************
	8
	9	man VIDIOC_ENUMAUDOUT(2)
	10
	11	Enumerate audio outputs
	12
	13
	14	Synopsis
	15	========
	16
	17	.. cpp:function:: int ioctl( int fd, int request, struct v4l2_audioout *argp )
	18
	19	Arguments
	20	=========
	21
	22	``fd``
	23	File descriptor returned by :ref:`open() <func-open>`.
	24
	25	``request``
	26	VIDIOC_ENUMAUDOUT
	27
	28	``argp``
	29
	30
	31	Description
	32	===========
	33
	34	To query the attributes of an audio output applications initialize the
	35	``index`` field and zero out the ``reserved`` array of a struct
	36	:ref:`v4l2_audioout <v4l2-audioout>` and call the ``VIDIOC_G_AUDOUT``
	37	ioctl with a pointer to this structure. Drivers fill the rest of the
	38	structure or return an ``EINVAL`` error code when the index is out of
	39	bounds. To enumerate all audio outputs applications shall begin at index
	40	zero, incrementing by one until the driver returns ``EINVAL``.
	41
	42	Note connectors on a TV card to loop back the received audio signal to a
	43	sound card are not audio outputs in this sense.
	44
	45	See :ref:`VIDIOC_G_AUDIOout <VIDIOC_G_AUDIOout>` for a description of struct
	46	:ref:`v4l2_audioout <v4l2-audioout>`.
	47
	48
	49	Return Value
	50	============
	51
	52	On success 0 is returned, on error -1 and the ``errno`` variable is set
	53	appropriately. The generic error codes are described at the
	54	:ref:`Generic Error Codes <gen-errors>` chapter.
	55
	56	EINVAL
	57	The number of the audio output is out of bounds.