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Diffstat (limited to 'Documentation/media/uapi/v4l/vidioc-enumaudioout.rst')
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diff --git a/Documentation/media/uapi/v4l/vidioc-enumaudioout.rst b/Documentation/media/uapi/v4l/vidioc-enumaudioout.rst new file mode 100644 index 000000000000..cde1db55834f --- /dev/null +++ b/Documentation/media/uapi/v4l/vidioc-enumaudioout.rst @@ -0,0 +1,59 @@ +.. -*- coding: utf-8; mode: rst -*- + +.. _VIDIOC_ENUMAUDOUT: + +*********************** +ioctl VIDIOC_ENUMAUDOUT +*********************** + +Name +==== + +VIDIOC_ENUMAUDOUT - Enumerate audio outputs + + +Synopsis +======== + +.. cpp:function:: int ioctl( int fd, int request, struct v4l2_audioout *argp ) + + +Arguments +========= + +``fd`` + File descriptor returned by :ref:`open() <func-open>`. + +``request`` + VIDIOC_ENUMAUDOUT + +``argp`` + + +Description +=========== + +To query the attributes of an audio output applications initialize the +``index`` field and zero out the ``reserved`` array of a struct +:ref:`v4l2_audioout <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 +:ref:`v4l2_audioout <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. |