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Diffstat (limited to 'Documentation/media/uapi/v4l/vidioc-g-std.rst')
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diff --git a/Documentation/media/uapi/v4l/vidioc-g-std.rst b/Documentation/media/uapi/v4l/vidioc-g-std.rst new file mode 100644 index 000000000000..5c2b861f8d26 --- /dev/null +++ b/Documentation/media/uapi/v4l/vidioc-g-std.rst @@ -0,0 +1,68 @@ +.. -*- coding: utf-8; mode: rst -*- + +.. _VIDIOC_G_STD: + +******************************** +ioctl VIDIOC_G_STD, VIDIOC_S_STD +******************************** + +Name +==== + +VIDIOC_G_STD - VIDIOC_S_STD - Query or select the video standard of the current input + + +Synopsis +======== + +.. cpp:function:: int ioctl( int fd, int request, v4l2_std_id *argp ) + +.. cpp:function:: int ioctl( int fd, int request, const v4l2_std_id *argp ) + + +Arguments +========= + +``fd`` + File descriptor returned by :ref:`open() <func-open>`. + +``request`` + VIDIOC_G_STD, VIDIOC_S_STD + +``argp`` + + +Description +=========== + +To query and select the current video standard applications use the +:ref:`VIDIOC_G_STD <VIDIOC_G_STD>` and :ref:`VIDIOC_S_STD <VIDIOC_G_STD>` ioctls which take a pointer to a +:ref:`v4l2_std_id <v4l2-std-id>` type as argument. :ref:`VIDIOC_G_STD <VIDIOC_G_STD>` +can return a single flag or a set of flags as in struct +:ref:`v4l2_standard <v4l2-standard>` field ``id``. The flags must be +unambiguous such that they appear in only one enumerated +:ref:`struct v4l2_standard <v4l2-standard>` structure. + +:ref:`VIDIOC_S_STD <VIDIOC_G_STD>` accepts one or more flags, being a write-only ioctl it +does not return the actual new standard as :ref:`VIDIOC_G_STD <VIDIOC_G_STD>` does. When +no flags are given or the current input does not support the requested +standard the driver returns an ``EINVAL`` error code. When the standard set +is ambiguous drivers may return ``EINVAL`` or choose any of the requested +standards. If the current input or output does not support standard +video timings (e.g. if :ref:`VIDIOC_ENUMINPUT` +does not set the ``V4L2_IN_CAP_STD`` flag), then ``ENODATA`` error code is +returned. + + +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 :ref:`VIDIOC_S_STD <VIDIOC_G_STD>` parameter was unsuitable. + +ENODATA + Standard video timings are not supported for this input or output. |