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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 | ||
b7e67f6c | 18 | .. cpp:function:: int ioctl( int fd, int request, int *argp ) |
5377d91f | 19 | |
586027ce | 20 | |
15e7d615 | 21 | Arguments |
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22 | ========= |
23 | ||
24 | ``fd`` | |
25 | File descriptor returned by :ref:`open() <func-open>`. | |
26 | ||
27 | ``request`` | |
28 | VIDIOC_G_INPUT, VIDIOC_S_INPUT | |
29 | ||
30 | ``argp`` | |
31 | ||
32 | ||
15e7d615 | 33 | Description |
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34 | =========== |
35 | ||
36 | To query the current video input applications call the | |
4e03cb76 | 37 | :ref:`VIDIOC_G_INPUT <VIDIOC_G_INPUT>` ioctl with a pointer to an integer where the driver |
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38 | stores the number of the input, as in the struct |
39 | :ref:`v4l2_input <v4l2-input>` ``index`` field. This ioctl will fail | |
cdb4af0f | 40 | only when there are no video inputs, returning ``EINVAL``. |
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41 | |
42 | To select a video input applications store the number of the desired | |
2212ff25 | 43 | input in an integer and call the :ref:`VIDIOC_S_INPUT <VIDIOC_G_INPUT>` ioctl with a pointer |
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44 | to this integer. Side effects are possible. For example inputs may |
45 | support different video standards, so the driver may implicitly switch | |
46 | the current standard. Because of these possible side effects | |
47 | applications must select an input before querying or negotiating any | |
48 | other parameters. | |
49 | ||
50 | Information about video inputs is available using the | |
7347081e | 51 | :ref:`VIDIOC_ENUMINPUT` ioctl. |
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52 | |
53 | ||
15e7d615 | 54 | Return Value |
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55 | ============ |
56 | ||
57 | On success 0 is returned, on error -1 and the ``errno`` variable is set | |
58 | appropriately. The generic error codes are described at the | |
59 | :ref:`Generic Error Codes <gen-errors>` chapter. | |
60 | ||
61 | EINVAL | |
62 | The number of the video input is out of bounds. |