60 lines
1.4 KiB
ReStructuredText
60 lines
1.4 KiB
ReStructuredText
.. -*- coding: utf-8; mode: rst -*-
|
|
|
|
.. _VIDIOC_ENUMAUDOUT:
|
|
|
|
***********************
|
|
ioctl VIDIOC_ENUMAUDOUT
|
|
***********************
|
|
|
|
Name
|
|
====
|
|
|
|
VIDIOC_ENUMAUDOUT - Enumerate audio outputs
|
|
|
|
|
|
Synopsis
|
|
========
|
|
|
|
.. c:function:: int ioctl( int fd, VIDIOC_ENUMAUDOUT, struct v4l2_audioout *argp )
|
|
:name: VIDIOC_ENUMAUDOUT
|
|
|
|
|
|
Arguments
|
|
=========
|
|
|
|
``fd``
|
|
File descriptor returned by :ref:`open() <func-open>`.
|
|
|
|
``argp``
|
|
|
|
|
|
Description
|
|
===========
|
|
|
|
To query the attributes of an audio output applications initialize the
|
|
``index`` field and zero out the ``reserved`` array of a struct
|
|
:c:type:`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_AUDOUT>` for a description of struct
|
|
:c:type:`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.
|