| .. 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. |
