Markus Heiser | 5377d91 | 2016-06-30 15:18:56 +0200 | [diff] [blame] | 1 | .. -*- coding: utf-8; mode: rst -*- |
| 2 | |
Mauro Carvalho Chehab | af4a4d0 | 2016-07-01 13:42:29 -0300 | [diff] [blame] | 3 | .. _VIDIOC_G_INPUT: |
Markus Heiser | 5377d91 | 2016-06-30 15:18:56 +0200 | [diff] [blame] | 4 | |
| 5 | ************************************ |
| 6 | ioctl VIDIOC_G_INPUT, VIDIOC_S_INPUT |
| 7 | ************************************ |
| 8 | |
Mauro Carvalho Chehab | 15e7d61 | 2016-07-05 15:14:35 -0300 | [diff] [blame^] | 9 | Name |
Mauro Carvalho Chehab | 586027c | 2016-07-05 07:58:48 -0300 | [diff] [blame] | 10 | ==== |
Markus Heiser | 5377d91 | 2016-06-30 15:18:56 +0200 | [diff] [blame] | 11 | |
Mauro Carvalho Chehab | 586027c | 2016-07-05 07:58:48 -0300 | [diff] [blame] | 12 | VIDIOC_G_INPUT - VIDIOC_S_INPUT - Query or select the current video input |
Markus Heiser | 5377d91 | 2016-06-30 15:18:56 +0200 | [diff] [blame] | 13 | |
Mauro Carvalho Chehab | 15e7d61 | 2016-07-05 15:14:35 -0300 | [diff] [blame^] | 14 | |
| 15 | Synopsis |
Markus Heiser | 5377d91 | 2016-06-30 15:18:56 +0200 | [diff] [blame] | 16 | ======== |
| 17 | |
Mauro Carvalho Chehab | b7e67f6 | 2016-07-02 09:49:16 -0300 | [diff] [blame] | 18 | .. cpp:function:: int ioctl( int fd, int request, int *argp ) |
Markus Heiser | 5377d91 | 2016-06-30 15:18:56 +0200 | [diff] [blame] | 19 | |
Mauro Carvalho Chehab | 586027c | 2016-07-05 07:58:48 -0300 | [diff] [blame] | 20 | |
Mauro Carvalho Chehab | 15e7d61 | 2016-07-05 15:14:35 -0300 | [diff] [blame^] | 21 | Arguments |
Markus Heiser | 5377d91 | 2016-06-30 15:18:56 +0200 | [diff] [blame] | 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 | |
Mauro Carvalho Chehab | 15e7d61 | 2016-07-05 15:14:35 -0300 | [diff] [blame^] | 33 | Description |
Markus Heiser | 5377d91 | 2016-06-30 15:18:56 +0200 | [diff] [blame] | 34 | =========== |
| 35 | |
| 36 | To query the current video input applications call the |
Mauro Carvalho Chehab | 4e03cb7 | 2016-07-03 10:02:29 -0300 | [diff] [blame] | 37 | :ref:`VIDIOC_G_INPUT <VIDIOC_G_INPUT>` ioctl with a pointer to an integer where the driver |
Markus Heiser | 5377d91 | 2016-06-30 15:18:56 +0200 | [diff] [blame] | 38 | stores the number of the input, as in the struct |
| 39 | :ref:`v4l2_input <v4l2-input>` ``index`` field. This ioctl will fail |
Mauro Carvalho Chehab | cdb4af0 | 2016-07-03 11:53:09 -0300 | [diff] [blame] | 40 | only when there are no video inputs, returning ``EINVAL``. |
Markus Heiser | 5377d91 | 2016-06-30 15:18:56 +0200 | [diff] [blame] | 41 | |
| 42 | To select a video input applications store the number of the desired |
Mauro Carvalho Chehab | 2212ff2 | 2016-07-01 14:33:56 -0300 | [diff] [blame] | 43 | input in an integer and call the :ref:`VIDIOC_S_INPUT <VIDIOC_G_INPUT>` ioctl with a pointer |
Markus Heiser | 5377d91 | 2016-06-30 15:18:56 +0200 | [diff] [blame] | 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 |
Mauro Carvalho Chehab | 7347081 | 2016-07-01 13:58:44 -0300 | [diff] [blame] | 51 | :ref:`VIDIOC_ENUMINPUT` ioctl. |
Markus Heiser | 5377d91 | 2016-06-30 15:18:56 +0200 | [diff] [blame] | 52 | |
| 53 | |
Mauro Carvalho Chehab | 15e7d61 | 2016-07-05 15:14:35 -0300 | [diff] [blame^] | 54 | Return Value |
Markus Heiser | 5377d91 | 2016-06-30 15:18:56 +0200 | [diff] [blame] | 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. |