1 .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later 2 .. c:namespace:: V4L 3 4 .. _VIDIOC_ENUMAUDIO: 5 6 ********************** 7 ioctl VIDIOC_ENUMAUDIO 8 ********************** 9 10 Name 11 ==== 12 13 VIDIOC_ENUMAUDIO - Enumerate audio inputs 14 15 Synopsis 16 ======== 17 18 .. c:macro:: VIDIOC_ENUMAUDIO 19 20 ``int ioctl(int fd, VIDIOC_ENUMAUDIO, struct v4l2_audio *argp)`` 21 22 Arguments 23 ========= 24 25 ``fd`` 26 File descriptor returned by :c:func:`open()`. 27 28 ``argp`` 29 Pointer to struct :c:type:`v4l2_audio`. 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 :c:type:`v4l2_audio` and call the :ref:`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 <VIDIOC_G_AUDIO>` for a description of struct 43 :c:type:`v4l2_audio`. 44 45 Return Value 46 ============ 47 48 On success 0 is returned, on error -1 and the ``errno`` variable is set 49 appropriately. The generic error codes are described at the 50 :ref:`Generic Error Codes <gen-errors>` chapter. 51 52 EINVAL 53 The number of the audio input is out of bounds.
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