Documentation/linux_tv/media/v4l/vidioc-enumaudio.rst

   1 .. -*- coding: utf-8; mode: rst -*-
   2
   3 .. _VIDIOC_ENUMAUDIO:
   4
   5 **********************
   6 ioctl VIDIOC_ENUMAUDIO
   7 **********************
   8
   9 *man VIDIOC_ENUMAUDIO(2)*
  10
  11 Enumerate audio inputs
  12
  13
  14 Synopsis
  15 ========
  16
  17 .. c:function:: int ioctl( int fd, int request, struct v4l2_audio *argp )
  18
  19 Arguments
  20 =========
  21
  22 ``fd``
  23     File descriptor returned by :ref:`open() <func-open>`.
  24
  25 ``request``
  26     VIDIOC_ENUMAUDIO
  27
  28 ``argp``
  29
  30
  31 Description
  32 ===========
  33
  34 To query the attributes of an audio input applications initialize the
  35 ``index`` field and zero out the ``reserved`` array of a struct
  36 :ref:`v4l2_audio <v4l2-audio>` and call the ``VIDIOC_ENUMAUDIO``
  37 ioctl with a pointer to this structure. Drivers fill the rest of the
  38 structure or return an EINVAL error code when the index is out of
  39 bounds. To enumerate all audio inputs applications shall begin at index
  40 zero, incrementing by one until the driver returns EINVAL.
  41
  42 See :ref:`VIDIOC_G_AUDIO` for a description of struct
  43 :ref:`v4l2_audio <v4l2-audio>`.
  44
  45
  46 Return Value
  47 ============
  48
  49 On success 0 is returned, on error -1 and the ``errno`` variable is set
  50 appropriately. The generic error codes are described at the
  51 :ref:`Generic Error Codes <gen-errors>` chapter.
  52
  53 EINVAL
  54     The number of the audio input is out of bounds.
  55
  56
  57 .. ------------------------------------------------------------------------------
  58 .. This file was automatically converted from DocBook-XML with the dbxml
  59 .. library (https://github.com/return42/sphkerneldoc). The origin XML comes
  60 .. from the linux kernel, refer to:
  61 ..
  62 .. * https://github.com/torvalds/linux/tree/master/Documentation/DocBook
  63 .. ------------------------------------------------------------------------------