1 .. SPDX-License-Identifier: GFDL-1.1-no-invari !! 1 .. Permission is granted to copy, distribute and/or modify this
2 .. c:namespace:: V4L !! 2 .. document under the terms of the GNU Free Documentation License,
>> 3 .. Version 1.1 or any later version published by the Free Software
>> 4 .. Foundation, with no Invariant Sections, no Front-Cover Texts
>> 5 .. and no Back-Cover Texts. A copy of the license is included at
>> 6 .. Documentation/userspace-api/media/fdl-appendix.rst.
>> 7 ..
>> 8 .. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections
3 9
4 .. _VIDIOC_ENUMAUDOUT: 10 .. _VIDIOC_ENUMAUDOUT:
5 11
6 *********************** 12 ***********************
7 ioctl VIDIOC_ENUMAUDOUT 13 ioctl VIDIOC_ENUMAUDOUT
8 *********************** 14 ***********************
9 15
10 Name 16 Name
11 ==== 17 ====
12 18
13 VIDIOC_ENUMAUDOUT - Enumerate audio outputs 19 VIDIOC_ENUMAUDOUT - Enumerate audio outputs
14 20
>> 21
15 Synopsis 22 Synopsis
16 ======== 23 ========
17 24
18 .. c:macro:: VIDIOC_ENUMAUDOUT !! 25 .. c:function:: int ioctl( int fd, VIDIOC_ENUMAUDOUT, struct v4l2_audioout *argp )
>> 26 :name: VIDIOC_ENUMAUDOUT
19 27
20 ``int ioctl(int fd, VIDIOC_ENUMAUDOUT, struct <<
21 28
22 Arguments 29 Arguments
23 ========= 30 =========
24 31
25 ``fd`` 32 ``fd``
26 File descriptor returned by :c:func:`open( !! 33 File descriptor returned by :ref:`open() <func-open>`.
27 34
28 ``argp`` 35 ``argp``
29 Pointer to struct :c:type:`v4l2_audioout`. 36 Pointer to struct :c:type:`v4l2_audioout`.
30 37
>> 38
31 Description 39 Description
32 =========== 40 ===========
33 41
34 To query the attributes of an audio output app 42 To query the attributes of an audio output applications initialize the
35 ``index`` field and zero out the ``reserved`` 43 ``index`` field and zero out the ``reserved`` array of a struct
36 :c:type:`v4l2_audioout` and call the ``VIDIOC_ 44 :c:type:`v4l2_audioout` and call the ``VIDIOC_G_AUDOUT``
37 ioctl with a pointer to this structure. Driver 45 ioctl with a pointer to this structure. Drivers fill the rest of the
38 structure or return an ``EINVAL`` error code w 46 structure or return an ``EINVAL`` error code when the index is out of
39 bounds. To enumerate all audio outputs applica 47 bounds. To enumerate all audio outputs applications shall begin at index
40 zero, incrementing by one until the driver ret 48 zero, incrementing by one until the driver returns ``EINVAL``.
41 49
42 .. note:: 50 .. note::
43 51
44 Connectors on a TV card to loop back the r 52 Connectors on a TV card to loop back the received audio signal
45 to a sound card are not audio outputs in t 53 to a sound card are not audio outputs in this sense.
46 54
47 See :ref:`VIDIOC_G_AUDIOout <VIDIOC_G_AUDOUT>` 55 See :ref:`VIDIOC_G_AUDIOout <VIDIOC_G_AUDOUT>` for a description of struct
48 :c:type:`v4l2_audioout`. 56 :c:type:`v4l2_audioout`.
>> 57
49 58
50 Return Value 59 Return Value
51 ============ 60 ============
52 61
53 On success 0 is returned, on error -1 and the 62 On success 0 is returned, on error -1 and the ``errno`` variable is set
54 appropriately. The generic error codes are des 63 appropriately. The generic error codes are described at the
55 :ref:`Generic Error Codes <gen-errors>` chapte 64 :ref:`Generic Error Codes <gen-errors>` chapter.
56 65
57 EINVAL 66 EINVAL
58 The number of the audio output is out of b 67 The number of the audio output is out of bounds.
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