1 .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later 2 .. c:namespace:: V4L 3 4 .. _VIDIOC_G_INPUT: 5 6 ************************************ 7 ioctl VIDIOC_G_INPUT, VIDIOC_S_INPUT 8 ************************************ 9 10 Name 11 ==== 12 13 VIDIOC_G_INPUT - VIDIOC_S_INPUT - Query or select the current video input 14 15 Synopsis 16 ======== 17 18 .. c:macro:: VIDIOC_G_INPUT 19 20 ``int ioctl(int fd, VIDIOC_G_INPUT, int *argp)`` 21 22 .. c:macro:: VIDIOC_S_INPUT 23 24 ``int ioctl(int fd, VIDIOC_S_INPUT, int *argp)`` 25 26 Arguments 27 ========= 28 29 ``fd`` 30 File descriptor returned by :c:func:`open()`. 31 32 ``argp`` 33 Pointer an integer with input index. 34 35 Description 36 =========== 37 38 To query the current video input applications call the 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 struct 41 :c:type:`v4l2_input` ``index`` field. This ioctl will fail 42 only when there are no video inputs, returning ``EINVAL``. 43 44 To select a video input applications store the number of the desired 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. For example inputs may 47 support different video standards, so the driver may implicitly switch 48 the current standard. Because of these possible side effects 49 applications must select an input before querying or negotiating any 50 other parameters. 51 52 Information about video inputs is available using the 53 :ref:`VIDIOC_ENUMINPUT` ioctl. 54 55 Return Value 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.
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.