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1 | .. -*- coding: utf-8; mode: rst -*- |
2 | ||
af4a4d0d | 3 | .. _VIDIOC_G_INPUT: |
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4 | |
5 | ************************************ | |
6 | ioctl VIDIOC_G_INPUT, VIDIOC_S_INPUT | |
7 | ************************************ | |
8 | ||
15e7d615 | 9 | Name |
586027ce | 10 | ==== |
5377d91f | 11 | |
586027ce | 12 | VIDIOC_G_INPUT - VIDIOC_S_INPUT - Query or select the current video input |
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_G_INPUT, int *argp ) |
19 | :name: VIDIOC_G_INPUT | |
20 | ||
21 | .. c:function:: int ioctl( int fd, VIDIOC_S_INPUT, int *argp ) | |
22 | :name: VIDIOC_S_INPUT | |
5377d91f | 23 | |
586027ce | 24 | |
15e7d615 | 25 | Arguments |
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26 | ========= |
27 | ||
28 | ``fd`` | |
29 | File descriptor returned by :ref:`open() <func-open>`. | |
30 | ||
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31 | ``argp`` |
32 | ||
33 | ||
15e7d615 | 34 | Description |
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35 | =========== |
36 | ||
37 | To query the current video input applications call the | |
4e03cb76 | 38 | :ref:`VIDIOC_G_INPUT <VIDIOC_G_INPUT>` ioctl with a pointer to an integer where the driver |
5377d91f | 39 | stores the number of the input, as in the struct |
e8be7e97 | 40 | :c:type:`v4l2_input` ``index`` field. This ioctl will fail |
cdb4af0f | 41 | only when there are no video inputs, returning ``EINVAL``. |
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42 | |
43 | To select a video input applications store the number of the desired | |
2212ff25 | 44 | input in an integer and call the :ref:`VIDIOC_S_INPUT <VIDIOC_G_INPUT>` ioctl with a pointer |
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45 | to this integer. Side effects are possible. For example inputs may |
46 | support different video standards, so the driver may implicitly switch | |
47 | the current standard. Because of these possible side effects | |
48 | applications must select an input before querying or negotiating any | |
49 | other parameters. | |
50 | ||
51 | Information about video inputs is available using the | |
7347081e | 52 | :ref:`VIDIOC_ENUMINPUT` ioctl. |
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53 | |
54 | ||
15e7d615 | 55 | Return Value |
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56 | ============ |
57 | ||
58 | On success 0 is returned, on error -1 and the ``errno`` variable is set | |
59 | appropriately. The generic error codes are described at the | |
60 | :ref:`Generic Error Codes <gen-errors>` chapter. | |
61 | ||
62 | EINVAL | |
63 | The number of the video input is out of bounds. |