.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later .. c:namespace:: V4L

.. _VIDIOC_ENUMAUDOUT:

ioctl VIDIOC_ENUMAUDOUT

Name

VIDIOC_ENUMAUDOUT - Enumerate audio outputs

Synopsis

.. c:macro:: VIDIOC_ENUMAUDOUT

int ioctl(int fd, VIDIOC_ENUMAUDOUT, struct v4l2_audioout *argp)

Arguments

fd File descriptor returned by :c:func:open().

argp Pointer to struct :c:type:v4l2_audioout.

Description

To query the attributes of an audio output applications initialize the index field and zero out the reserved array of a struct :c:type:v4l2_audioout and call the VIDIOC_G_AUDOUT 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 outputs applications shall begin at index zero, incrementing by one until the driver returns EINVAL.

.. note::

Connectors on a TV card to loop back the received audio signal
to a sound card are not audio outputs in this sense.

See :ref:VIDIOC_G_AUDIOout <VIDIOC_G_AUDOUT> for a description of struct :c:type:v4l2_audioout.

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.

EINVAL The number of the audio output is out of bounds.