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Diffstat (limited to 'Documentation/media/uapi/v4l/vidioc-g-input.rst')
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diff --git a/Documentation/media/uapi/v4l/vidioc-g-input.rst b/Documentation/media/uapi/v4l/vidioc-g-input.rst new file mode 100644 index 000000000000..29e22f6f8028 --- /dev/null +++ b/Documentation/media/uapi/v4l/vidioc-g-input.rst @@ -0,0 +1,62 @@ +.. -*- coding: utf-8; mode: rst -*- + +.. _VIDIOC_G_INPUT: + +************************************ +ioctl VIDIOC_G_INPUT, VIDIOC_S_INPUT +************************************ + +Name +==== + +VIDIOC_G_INPUT - VIDIOC_S_INPUT - Query or select the current video input + + +Synopsis +======== + +.. cpp:function:: int ioctl( int fd, int request, int *argp ) + + +Arguments +========= + +``fd`` + File descriptor returned by :ref:`open() <func-open>`. + +``request`` + VIDIOC_G_INPUT, VIDIOC_S_INPUT + +``argp`` + + +Description +=========== + +To query the current video input applications call the +:ref:`VIDIOC_G_INPUT <VIDIOC_G_INPUT>` ioctl with a pointer to an integer where the driver +stores the number of the input, as in the struct +:ref:`v4l2_input <v4l2-input>` ``index`` field. This ioctl will fail +only when there are no video inputs, returning ``EINVAL``. + +To select a video input applications store the number of the desired +input in an integer and call the :ref:`VIDIOC_S_INPUT <VIDIOC_G_INPUT>` ioctl with a pointer +to this integer. Side effects are possible. For example inputs may +support different video standards, so the driver may implicitly switch +the current standard. Because of these possible side effects +applications must select an input before querying or negotiating any +other parameters. + +Information about video inputs is available using the +:ref:`VIDIOC_ENUMINPUT` ioctl. + + +Return Value +============ + +On success 0 is returned, on error -1 and the ``errno`` variable is set +appropriately. The generic error codes are described at the +:ref:`Generic Error Codes <gen-errors>` chapter. + +EINVAL + The number of the video input is out of bounds. |