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1 | .. -*- coding: utf-8; mode: rst -*- |
2 | ||
af4a4d0d | 3 | .. _VIDIOC_G_STD: |
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4 | |
5 | ******************************** | |
6 | ioctl VIDIOC_G_STD, VIDIOC_S_STD | |
7 | ******************************** | |
8 | ||
9 | *man VIDIOC_G_STD(2)* | |
10 | ||
11 | VIDIOC_S_STD | |
12 | Query or select the video standard of the current input | |
13 | ||
14 | ||
15 | Synopsis | |
16 | ======== | |
17 | ||
18 | .. c:function:: int ioctl( int fd, int request, v4l2_std_id *argp ) | |
19 | ||
20 | .. c:function:: int ioctl( int fd, int request, const v4l2_std_id *argp ) | |
21 | ||
22 | Arguments | |
23 | ========= | |
24 | ||
25 | ``fd`` | |
26 | File descriptor returned by :ref:`open() <func-open>`. | |
27 | ||
28 | ``request`` | |
29 | VIDIOC_G_STD, VIDIOC_S_STD | |
30 | ||
31 | ``argp`` | |
32 | ||
33 | ||
34 | Description | |
35 | =========== | |
36 | ||
37 | To query and select the current video standard applications use the | |
38 | ``VIDIOC_G_STD`` and ``VIDIOC_S_STD`` ioctls which take a pointer to a | |
39 | :ref:`v4l2_std_id <v4l2-std-id>` type as argument. ``VIDIOC_G_STD`` | |
40 | can return a single flag or a set of flags as in struct | |
41 | :ref:`v4l2_standard <v4l2-standard>` field ``id``. The flags must be | |
42 | unambiguous such that they appear in only one enumerated | |
43 | :c:type:`struct v4l2_standard` structure. | |
44 | ||
45 | ``VIDIOC_S_STD`` accepts one or more flags, being a write-only ioctl it | |
46 | does not return the actual new standard as ``VIDIOC_G_STD`` does. When | |
47 | no flags are given or the current input does not support the requested | |
48 | standard the driver returns an EINVAL error code. When the standard set | |
49 | is ambiguous drivers may return EINVAL or choose any of the requested | |
50 | standards. If the current input or output does not support standard | |
7347081e | 51 | video timings (e.g. if :ref:`VIDIOC_ENUMINPUT` |
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52 | does not set the ``V4L2_IN_CAP_STD`` flag), then ENODATA error code is |
53 | returned. | |
54 | ||
55 | ||
56 | Return Value | |
57 | ============ | |
58 | ||
59 | On success 0 is returned, on error -1 and the ``errno`` variable is set | |
60 | appropriately. The generic error codes are described at the | |
61 | :ref:`Generic Error Codes <gen-errors>` chapter. | |
62 | ||
63 | EINVAL | |
64 | The ``VIDIOC_S_STD`` parameter was unsuitable. | |
65 | ||
66 | ENODATA | |
67 | Standard video timings are not supported for this input or output. | |
68 | ||
69 | ||
70 | .. ------------------------------------------------------------------------------ | |
71 | .. This file was automatically converted from DocBook-XML with the dbxml | |
72 | .. library (https://github.com/return42/sphkerneldoc). The origin XML comes | |
73 | .. from the linux kernel, refer to: | |
74 | .. | |
75 | .. * https://github.com/torvalds/linux/tree/master/Documentation/DocBook | |
76 | .. ------------------------------------------------------------------------------ |