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1 | .. -*- coding: utf-8; mode: rst -*- |
2 | ||
9f97b306 | 3 | .. _VIDIOC_ENUMAUDOUT: |
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4 | |
5 | *********************** | |
6 | ioctl VIDIOC_ENUMAUDOUT | |
7 | *********************** | |
8 | ||
15e7d615 | 9 | Name |
586027ce | 10 | ==== |
5377d91f | 11 | |
586027ce | 12 | VIDIOC_ENUMAUDOUT - Enumerate audio outputs |
5377d91f | 13 | |
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14 | |
15 | Synopsis | |
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16 | ======== |
17 | ||
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18 | .. c:function:: int ioctl( int fd, VIDIOC_ENUMAUDOUT, struct v4l2_audioout *argp ) |
19 | :name: VIDIOC_ENUMAUDOUT | |
5377d91f | 20 | |
586027ce | 21 | |
15e7d615 | 22 | Arguments |
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23 | ========= |
24 | ||
25 | ``fd`` | |
26 | File descriptor returned by :ref:`open() <func-open>`. | |
27 | ||
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28 | ``argp`` |
29 | ||
30 | ||
15e7d615 | 31 | Description |
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32 | =========== |
33 | ||
34 | To query the attributes of an audio output applications initialize the | |
35 | ``index`` field and zero out the ``reserved`` array of a struct | |
e8be7e97 | 36 | :c:type:`v4l2_audioout` and call the ``VIDIOC_G_AUDOUT`` |
5377d91f | 37 | ioctl with a pointer to this structure. Drivers fill the rest of the |
cdb4af0f | 38 | structure or return an ``EINVAL`` error code when the index is out of |
5377d91f | 39 | bounds. To enumerate all audio outputs applications shall begin at index |
cdb4af0f | 40 | zero, incrementing by one until the driver returns ``EINVAL``. |
5377d91f | 41 | |
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42 | .. note:: |
43 | ||
44 | Connectors on a TV card to loop back the received audio signal | |
706f8a99 | 45 | to a sound card are not audio outputs in this sense. |
5377d91f | 46 | |
9f97b306 | 47 | See :ref:`VIDIOC_G_AUDIOout <VIDIOC_G_AUDOUT>` for a description of struct |
e8be7e97 | 48 | :c:type:`v4l2_audioout`. |
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49 | |
50 | ||
15e7d615 | 51 | Return Value |
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52 | ============ |
53 | ||
54 | On success 0 is returned, on error -1 and the ``errno`` variable is set | |
55 | appropriately. The generic error codes are described at the | |
56 | :ref:`Generic Error Codes <gen-errors>` chapter. | |
57 | ||
58 | EINVAL | |
59 | The number of the audio output is out of bounds. |