1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
2
3.. _VIDIOC_G_STD:
4
5**************************************************************************
6ioctl VIDIOC_G_STD, VIDIOC_S_STD, VIDIOC_SUBDEV_G_STD, VIDIOC_SUBDEV_S_STD
7**************************************************************************
8
9Name
10====
11
12VIDIOC_G_STD - VIDIOC_S_STD - VIDIOC_SUBDEV_G_STD - VIDIOC_SUBDEV_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.. c:function:: int ioctl( int fd, VIDIOC_SUBDEV_G_STD, v4l2_std_id *argp )
25    :name: VIDIOC_SUBDEV_G_STD
26
27.. c:function:: int ioctl( int fd, VIDIOC_SUBDEV_S_STD, const v4l2_std_id *argp )
28    :name: VIDIOC_SUBDEV_S_STD
29
30
31Arguments
32=========
33
34``fd``
35    File descriptor returned by :ref:`open() <func-open>`.
36
37``argp``
38    Pointer to :c:type:`v4l2_std_id`.
39
40
41Description
42===========
43
44To query and select the current video standard applications use the
45:ref:`VIDIOC_G_STD <VIDIOC_G_STD>` and :ref:`VIDIOC_S_STD <VIDIOC_G_STD>` ioctls which take a pointer to a
46:ref:`v4l2_std_id <v4l2-std-id>` type as argument. :ref:`VIDIOC_G_STD <VIDIOC_G_STD>`
47can return a single flag or a set of flags as in struct
48:c:type:`v4l2_standard` field ``id``. The flags must be
49unambiguous such that they appear in only one enumerated
50struct :c:type:`v4l2_standard` structure.
51
52:ref:`VIDIOC_S_STD <VIDIOC_G_STD>` accepts one or more flags, being a write-only ioctl it
53does not return the actual new standard as :ref:`VIDIOC_G_STD <VIDIOC_G_STD>` does. When
54no flags are given or the current input does not support the requested
55standard the driver returns an ``EINVAL`` error code. When the standard set
56is ambiguous drivers may return ``EINVAL`` or choose any of the requested
57standards. If the current input or output does not support standard
58video timings (e.g. if :ref:`VIDIOC_ENUMINPUT`
59does not set the ``V4L2_IN_CAP_STD`` flag), then ``ENODATA`` error code is
60returned.
61
62Calling ``VIDIOC_SUBDEV_S_STD`` on a subdev device node that has been registered
63in read-only mode is not allowed. An error is returned and the errno variable is
64set to ``-EPERM``.
65
66Return Value
67============
68
69On success 0 is returned, on error -1 and the ``errno`` variable is set
70appropriately. The generic error codes are described at the
71:ref:`Generic Error Codes <gen-errors>` chapter.
72
73EINVAL
74    The :ref:`VIDIOC_S_STD <VIDIOC_G_STD>` parameter was unsuitable.
75
76ENODATA
77    Standard video timings are not supported for this input or output.
78
79EPERM
80    ``VIDIOC_SUBDEV_S_STD`` has been called on a read-only subdevice.
81