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.. document under the terms of the GNU Free Documentation License,
.. Version 1.1 or any later version published by the Free Software
.. Foundation, with no Invariant Sections, no Front-Cover Texts
.. and no Back-Cover Texts. A copy of the license is included at
.. Documentation/media/uapi/fdl-appendix.rst.
.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections
VIDIOC_ENUMAUDIO - Enumerate audio inputs
.. c:function:: int ioctl( int fd, VIDIOC_ENUMAUDIO, struct v4l2_audio *argp )
File descriptor returned by :ref:`open() <func-open>`.
Pointer to struct :c:type:`v4l2_audio`.
To query the attributes of an audio input applications initialize the
``index`` field and zero out the ``reserved`` array of a struct
:c:type:`v4l2_audio` and call the :ref:`VIDIOC_ENUMAUDIO`
ioctl with a pointer to this structure. Drivers fill the rest of the
structure or return an ``EINVAL`` error code when the index is out of
bounds. To enumerate all audio inputs applications shall begin at index
zero, incrementing by one until the driver returns ``EINVAL``.
See :ref:`VIDIOC_G_AUDIO <VIDIOC_G_AUDIO>` for a description of struct
Return Value
On success 0 is returned, on error -1 and the ``errno`` variable is set
appropriately. The generic error codes are described at the
:ref:`Generic Error Codes <gen-errors>` chapter.
The number of the audio input is out of bounds.