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1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later2.. c:namespace:: V4L3 4.. _VIDIOC_G_INPUT:5 6************************************7ioctl VIDIOC_G_INPUT, VIDIOC_S_INPUT8************************************9 10Name11====12 13VIDIOC_G_INPUT - VIDIOC_S_INPUT - Query or select the current video input14 15Synopsis16========17 18.. c:macro:: VIDIOC_G_INPUT19 20``int ioctl(int fd, VIDIOC_G_INPUT, int *argp)``21 22.. c:macro:: VIDIOC_S_INPUT23 24``int ioctl(int fd, VIDIOC_S_INPUT, int *argp)``25 26Arguments27=========28 29``fd``30 File descriptor returned by :c:func:`open()`.31 32``argp``33 Pointer an integer with input index.34 35Description36===========37 38To query the current video input applications call the39:ref:`VIDIOC_G_INPUT <VIDIOC_G_INPUT>` ioctl with a pointer to an integer where the driver40stores the number of the input, as in the struct41:c:type:`v4l2_input` ``index`` field. This ioctl will fail42only when there are no video inputs, returning ``EINVAL``.43 44To select a video input applications store the number of the desired45input in an integer and call the :ref:`VIDIOC_S_INPUT <VIDIOC_G_INPUT>` ioctl with a pointer46to this integer. Side effects are possible. For example inputs may47support different video standards, so the driver may implicitly switch48the current standard. Because of these possible side effects49applications must select an input before querying or negotiating any50other parameters.51 52Information about video inputs is available using the53:ref:`VIDIOC_ENUMINPUT` ioctl.54 55Return Value56============57 58On success 0 is returned, on error -1 and the ``errno`` variable is set59appropriately. The generic error codes are described at the60:ref:`Generic Error Codes <gen-errors>` chapter.61 62EINVAL63 The number of the video input is out of bounds.64