1.. -*- coding: utf-8; mode: rst -*- 2 3.. _VIDIOC_G_STD: 4 5******************************** 6ioctl VIDIOC_G_STD, VIDIOC_S_STD 7******************************** 8 9Name 10==== 11 12VIDIOC_G_STD - VIDIOC_S_STD - Query or select the video standard of the current input 13 14 15Synopsis 16======== 17 18.. c:function:: int ioctl( int fd, VIDIOC_G_STD, v4l2_std_id *argp ) 19 :name: VIDIOC_G_STD 20 21.. c:function:: int ioctl( int fd, VIDIOC_S_STD, const v4l2_std_id *argp ) 22 :name: VIDIOC_S_STD 23 24 25Arguments 26========= 27 28``fd`` 29 File descriptor returned by :ref:`open() <func-open>`. 30 31``argp`` 32 Pointer to :c:type:`v4l2_std_id`. 33 34 35Description 36=========== 37 38To query and select the current video standard applications use the 39:ref:`VIDIOC_G_STD <VIDIOC_G_STD>` and :ref:`VIDIOC_S_STD <VIDIOC_G_STD>` ioctls which take a pointer to a 40:ref:`v4l2_std_id <v4l2-std-id>` type as argument. :ref:`VIDIOC_G_STD <VIDIOC_G_STD>` 41can return a single flag or a set of flags as in struct 42:c:type:`v4l2_standard` field ``id``. The flags must be 43unambiguous such that they appear in only one enumerated 44struct :c:type:`v4l2_standard` structure. 45 46:ref:`VIDIOC_S_STD <VIDIOC_G_STD>` accepts one or more flags, being a write-only ioctl it 47does not return the actual new standard as :ref:`VIDIOC_G_STD <VIDIOC_G_STD>` does. When 48no flags are given or the current input does not support the requested 49standard the driver returns an ``EINVAL`` error code. When the standard set 50is ambiguous drivers may return ``EINVAL`` or choose any of the requested 51standards. If the current input or output does not support standard 52video timings (e.g. if :ref:`VIDIOC_ENUMINPUT` 53does not set the ``V4L2_IN_CAP_STD`` flag), then ``ENODATA`` error code is 54returned. 55 56 57Return Value 58============ 59 60On success 0 is returned, on error -1 and the ``errno`` variable is set 61appropriately. The generic error codes are described at the 62:ref:`Generic Error Codes <gen-errors>` chapter. 63 64EINVAL 65 The :ref:`VIDIOC_S_STD <VIDIOC_G_STD>` parameter was unsuitable. 66 67ENODATA 68 Standard video timings are not supported for this input or output. 69