1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later 2.. c:namespace:: V4L 3 4.. _VIDIOC_ENUMAUDIO: 5 6********************** 7ioctl VIDIOC_ENUMAUDIO 8********************** 9 10Name 11==== 12 13VIDIOC_ENUMAUDIO - Enumerate audio inputs 14 15Synopsis 16======== 17 18.. c:macro:: VIDIOC_ENUMAUDIO 19 20``int ioctl(int fd, VIDIOC_ENUMAUDIO, struct v4l2_audio *argp)`` 21 22Arguments 23========= 24 25``fd`` 26 File descriptor returned by :c:func:`open()`. 27 28``argp`` 29 Pointer to struct :c:type:`v4l2_audio`. 30 31Description 32=========== 33 34To 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` 37ioctl with a pointer to this structure. Drivers fill the rest of the 38structure or return an ``EINVAL`` error code when the index is out of 39bounds. To enumerate all audio inputs applications shall begin at index 40zero, incrementing by one until the driver returns ``EINVAL``. 41 42See :ref:`VIDIOC_G_AUDIO <VIDIOC_G_AUDIO>` for a description of struct 43:c:type:`v4l2_audio`. 44 45Return Value 46============ 47 48On success 0 is returned, on error -1 and the ``errno`` variable is set 49appropriately. The generic error codes are described at the 50:ref:`Generic Error Codes <gen-errors>` chapter. 51 52EINVAL 53 The number of the audio input is out of bounds. 54