1*4882a593Smuzhiyun.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later 2*4882a593Smuzhiyun.. c:namespace:: V4L 3*4882a593Smuzhiyun 4*4882a593Smuzhiyun.. _VIDIOC_G_INPUT: 5*4882a593Smuzhiyun 6*4882a593Smuzhiyun************************************ 7*4882a593Smuzhiyunioctl VIDIOC_G_INPUT, VIDIOC_S_INPUT 8*4882a593Smuzhiyun************************************ 9*4882a593Smuzhiyun 10*4882a593SmuzhiyunName 11*4882a593Smuzhiyun==== 12*4882a593Smuzhiyun 13*4882a593SmuzhiyunVIDIOC_G_INPUT - VIDIOC_S_INPUT - Query or select the current video input 14*4882a593Smuzhiyun 15*4882a593SmuzhiyunSynopsis 16*4882a593Smuzhiyun======== 17*4882a593Smuzhiyun 18*4882a593Smuzhiyun.. c:macro:: VIDIOC_G_INPUT 19*4882a593Smuzhiyun 20*4882a593Smuzhiyun``int ioctl(int fd, VIDIOC_G_INPUT, int *argp)`` 21*4882a593Smuzhiyun 22*4882a593Smuzhiyun.. c:macro:: VIDIOC_S_INPUT 23*4882a593Smuzhiyun 24*4882a593Smuzhiyun``int ioctl(int fd, VIDIOC_S_INPUT, int *argp)`` 25*4882a593Smuzhiyun 26*4882a593SmuzhiyunArguments 27*4882a593Smuzhiyun========= 28*4882a593Smuzhiyun 29*4882a593Smuzhiyun``fd`` 30*4882a593Smuzhiyun File descriptor returned by :c:func:`open()`. 31*4882a593Smuzhiyun 32*4882a593Smuzhiyun``argp`` 33*4882a593Smuzhiyun Pointer an integer with input index. 34*4882a593Smuzhiyun 35*4882a593SmuzhiyunDescription 36*4882a593Smuzhiyun=========== 37*4882a593Smuzhiyun 38*4882a593SmuzhiyunTo query the current video input applications call the 39*4882a593Smuzhiyun:ref:`VIDIOC_G_INPUT <VIDIOC_G_INPUT>` ioctl with a pointer to an integer where the driver 40*4882a593Smuzhiyunstores the number of the input, as in the struct 41*4882a593Smuzhiyun:c:type:`v4l2_input` ``index`` field. This ioctl will fail 42*4882a593Smuzhiyunonly when there are no video inputs, returning ``EINVAL``. 43*4882a593Smuzhiyun 44*4882a593SmuzhiyunTo select a video input applications store the number of the desired 45*4882a593Smuzhiyuninput in an integer and call the :ref:`VIDIOC_S_INPUT <VIDIOC_G_INPUT>` ioctl with a pointer 46*4882a593Smuzhiyunto this integer. Side effects are possible. For example inputs may 47*4882a593Smuzhiyunsupport different video standards, so the driver may implicitly switch 48*4882a593Smuzhiyunthe current standard. Because of these possible side effects 49*4882a593Smuzhiyunapplications must select an input before querying or negotiating any 50*4882a593Smuzhiyunother parameters. 51*4882a593Smuzhiyun 52*4882a593SmuzhiyunInformation about video inputs is available using the 53*4882a593Smuzhiyun:ref:`VIDIOC_ENUMINPUT` ioctl. 54*4882a593Smuzhiyun 55*4882a593SmuzhiyunReturn Value 56*4882a593Smuzhiyun============ 57*4882a593Smuzhiyun 58*4882a593SmuzhiyunOn success 0 is returned, on error -1 and the ``errno`` variable is set 59*4882a593Smuzhiyunappropriately. The generic error codes are described at the 60*4882a593Smuzhiyun:ref:`Generic Error Codes <gen-errors>` chapter. 61*4882a593Smuzhiyun 62*4882a593SmuzhiyunEINVAL 63*4882a593Smuzhiyun The number of the video input is out of bounds. 64