1 .. SPDX-License-Identifier: GFDL-1.1-no-invari 1 .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
2 .. c:namespace:: V4L 2 .. c:namespace:: V4L
3 3
4 .. _VIDIOC_G_INPUT: 4 .. _VIDIOC_G_INPUT:
5 5
6 ************************************ 6 ************************************
7 ioctl VIDIOC_G_INPUT, VIDIOC_S_INPUT 7 ioctl VIDIOC_G_INPUT, VIDIOC_S_INPUT
8 ************************************ 8 ************************************
9 9
10 Name 10 Name
11 ==== 11 ====
12 12
13 VIDIOC_G_INPUT - VIDIOC_S_INPUT - Query or sel 13 VIDIOC_G_INPUT - VIDIOC_S_INPUT - Query or select the current video input
14 14
15 Synopsis 15 Synopsis
16 ======== 16 ========
17 17
18 .. c:macro:: VIDIOC_G_INPUT 18 .. c:macro:: VIDIOC_G_INPUT
19 19
20 ``int ioctl(int fd, VIDIOC_G_INPUT, int *argp) 20 ``int ioctl(int fd, VIDIOC_G_INPUT, int *argp)``
21 21
22 .. c:macro:: VIDIOC_S_INPUT 22 .. c:macro:: VIDIOC_S_INPUT
23 23
24 ``int ioctl(int fd, VIDIOC_S_INPUT, int *argp) 24 ``int ioctl(int fd, VIDIOC_S_INPUT, int *argp)``
25 25
26 Arguments 26 Arguments
27 ========= 27 =========
28 28
29 ``fd`` 29 ``fd``
30 File descriptor returned by :c:func:`open( 30 File descriptor returned by :c:func:`open()`.
31 31
32 ``argp`` 32 ``argp``
33 Pointer an integer with input index. 33 Pointer an integer with input index.
34 34
35 Description 35 Description
36 =========== 36 ===========
37 37
38 To query the current video input applications 38 To query the current video input applications call the
39 :ref:`VIDIOC_G_INPUT <VIDIOC_G_INPUT>` ioctl w 39 :ref:`VIDIOC_G_INPUT <VIDIOC_G_INPUT>` ioctl with a pointer to an integer where the driver
40 stores the number of the input, as in the stru 40 stores the number of the input, as in the struct
41 :c:type:`v4l2_input` ``index`` field. This ioc 41 :c:type:`v4l2_input` ``index`` field. This ioctl will fail
42 only when there are no video inputs, returning 42 only when there are no video inputs, returning ``EINVAL``.
43 43
44 To select a video input applications store the 44 To select a video input applications store the number of the desired
45 input in an integer and call the :ref:`VIDIOC_ 45 input in an integer and call the :ref:`VIDIOC_S_INPUT <VIDIOC_G_INPUT>` ioctl with a pointer
46 to this integer. Side effects are possible. Fo 46 to this integer. Side effects are possible. For example inputs may
47 support different video standards, so the driv 47 support different video standards, so the driver may implicitly switch
48 the current standard. Because of these possibl 48 the current standard. Because of these possible side effects
49 applications must select an input before query 49 applications must select an input before querying or negotiating any
50 other parameters. 50 other parameters.
51 51
52 Information about video inputs is available us 52 Information about video inputs is available using the
53 :ref:`VIDIOC_ENUMINPUT` ioctl. 53 :ref:`VIDIOC_ENUMINPUT` ioctl.
54 54
55 Return Value 55 Return Value
56 ============ 56 ============
57 57
58 On success 0 is returned, on error -1 and the 58 On success 0 is returned, on error -1 and the ``errno`` variable is set
59 appropriately. The generic error codes are des 59 appropriately. The generic error codes are described at the
60 :ref:`Generic Error Codes <gen-errors>` chapte 60 :ref:`Generic Error Codes <gen-errors>` chapter.
61 61
62 EINVAL 62 EINVAL
63 The number of the video input is out of bo 63 The number of the video input is out of bounds.
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