1 .. -*- coding: utf-8; mode: rst -*-
5 ***********************
6 ioctl VIDIOC_ENUMAUDOUT
7 ***********************
12 VIDIOC_ENUMAUDOUT - Enumerate audio outputs
18 .. cpp:function:: int ioctl( int fd, int request, struct v4l2_audioout *argp )
25 File descriptor returned by :ref:`open() <func-open>`.
36 To query the attributes of an audio output applications initialize the
37 ``index`` field and zero out the ``reserved`` array of a struct
38 :ref:`v4l2_audioout <v4l2-audioout>` and call the ``VIDIOC_G_AUDOUT``
39 ioctl with a pointer to this structure. Drivers fill the rest of the
40 structure or return an ``EINVAL`` error code when the index is out of
41 bounds. To enumerate all audio outputs applications shall begin at index
42 zero, incrementing by one until the driver returns ``EINVAL``.
44 .. note:: Connectors on a TV card to loop back the received audio signal
45 to a sound card are not audio outputs in this sense.
47 See :ref:`VIDIOC_G_AUDIOout <VIDIOC_G_AUDOUT>` for a description of struct
48 :ref:`v4l2_audioout <v4l2-audioout>`.
54 On success 0 is returned, on error -1 and the ``errno`` variable is set
55 appropriately. The generic error codes are described at the
56 :ref:`Generic Error Codes <gen-errors>` chapter.
59 The number of the audio output is out of bounds.