[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
5377d91f MH	1	.. -- coding: utf-8; mode: rst --
5377d91f MH	2
af4a4d0d	3	.. _VIDIOC_ENUMAUDIOOUT:
5377d91f MH	4
	5	***********************
	6	ioctl VIDIOC_ENUMAUDOUT
	7	***********************
	8
	9	man VIDIOC_ENUMAUDOUT(2)
	10
	11	Enumerate audio outputs
	12
	13
	14	Synopsis
	15	========
	16
b7e67f6c	17	.. cpp:function:: int ioctl( int fd, int request, struct v4l2_audioout *argp )
5377d91f MH	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
cdb4af0f	38	structure or return an ``EINVAL`` error code when the index is out of
5377d91f	39	bounds. To enumerate all audio outputs applications shall begin at index
cdb4af0f	40	zero, incrementing by one until the driver returns ``EINVAL``.
5377d91f MH	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
4e03cb76	45	See :ref:`VIDIOC_G_AUDIOout <VIDIOC_G_AUDIOout>` for a description of struct
5377d91f MH	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.