1 .. Permission is granted to copy, distribute and/or modify this
2 .. document under the terms of the GNU Free Documentation License,
3 .. Version 1.1 or any later version published by the Free Software
4 .. Foundation, with no Invariant Sections, no Front-Cover Texts
5 .. and no Back-Cover Texts. A copy of the license is included at
6 .. Documentation/userspace-api/media/fdl-appendix.rst.
8 .. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections
12 ************************************
13 ioctl VIDIOC_G_INPUT, VIDIOC_S_INPUT
14 ************************************
19 VIDIOC_G_INPUT - VIDIOC_S_INPUT - Query or select the current video input
25 .. c:function:: int ioctl( int fd, VIDIOC_G_INPUT, int *argp )
28 .. c:function:: int ioctl( int fd, VIDIOC_S_INPUT, int *argp )
36 File descriptor returned by :ref:`open() <func-open>`.
39 Pointer an integer with input index.
45 To query the current video input applications call the
46 :ref:`VIDIOC_G_INPUT <VIDIOC_G_INPUT>` ioctl with a pointer to an integer where the driver
47 stores the number of the input, as in the struct
48 :c:type:`v4l2_input` ``index`` field. This ioctl will fail
49 only when there are no video inputs, returning ``EINVAL``.
51 To select a video input applications store the number of the desired
52 input in an integer and call the :ref:`VIDIOC_S_INPUT <VIDIOC_G_INPUT>` ioctl with a pointer
53 to this integer. Side effects are possible. For example inputs may
54 support different video standards, so the driver may implicitly switch
55 the current standard. Because of these possible side effects
56 applications must select an input before querying or negotiating any
59 Information about video inputs is available using the
60 :ref:`VIDIOC_ENUMINPUT` ioctl.
66 On success 0 is returned, on error -1 and the ``errno`` variable is set
67 appropriately. The generic error codes are described at the
68 :ref:`Generic Error Codes <gen-errors>` chapter.
71 The number of the video input is out of bounds.