1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
2
3.. _VIDIOC_ENUMAUDIO:
4
5**********************
6ioctl VIDIOC_ENUMAUDIO
7**********************
8
9Name
10====
11
12VIDIOC_ENUMAUDIO - Enumerate audio inputs
13
14
15Synopsis
16========
17
18.. c:function:: int ioctl( int fd, VIDIOC_ENUMAUDIO, struct v4l2_audio *argp )
19    :name: VIDIOC_ENUMAUDIO
20
21
22Arguments
23=========
24
25``fd``
26    File descriptor returned by :ref:`open() <func-open>`.
27
28``argp``
29    Pointer to struct :c:type:`v4l2_audio`.
30
31
32Description
33===========
34
35To query the attributes of an audio input applications initialize the
36``index`` field and zero out the ``reserved`` array of a struct
37:c:type:`v4l2_audio` and call the :ref:`VIDIOC_ENUMAUDIO`
38ioctl with a pointer to this structure. Drivers fill the rest of the
39structure or return an ``EINVAL`` error code when the index is out of
40bounds. To enumerate all audio inputs applications shall begin at index
41zero, incrementing by one until the driver returns ``EINVAL``.
42
43See :ref:`VIDIOC_G_AUDIO <VIDIOC_G_AUDIO>` for a description of struct
44:c:type:`v4l2_audio`.
45
46
47Return Value
48============
49
50On success 0 is returned, on error -1 and the ``errno`` variable is set
51appropriately. The generic error codes are described at the
52:ref:`Generic Error Codes <gen-errors>` chapter.
53
54EINVAL
55    The number of the audio input is out of bounds.
56