projects / deliverable / linux.git / blame
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|---|---|---|
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1 | .. -*- coding: utf-8; mode: rst -*- |
| 2 | ||
| af4a4d0d | 3 | .. _VIDIOC_G_STD: |
| 5377d91f MH |
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 | ||
| b7e67f6c | 18 | .. cpp:function:: int ioctl( int fd, int request, v4l2_std_id *argp ) |
| 5377d91f | 19 | |
| b7e67f6c | 20 | .. cpp:function:: int ioctl( int fd, int request, const v4l2_std_id *argp ) |
| 5377d91f MH |
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 | |
| 4e03cb76 MCC |
38 | :ref:`VIDIOC_G_STD <VIDIOC_G_STD>` and :ref:`VIDIOC_S_STD <VIDIOC_G_STD>` ioctls which take a pointer to a |
| 39 | :ref:`v4l2_std_id <v4l2-std-id>` type as argument. :ref:`VIDIOC_G_STD <VIDIOC_G_STD>` | |
| 5377d91f MH |
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 | ||
| 2212ff25 | 45 | :ref:`VIDIOC_S_STD <VIDIOC_G_STD>` accepts one or more flags, being a write-only ioctl it |
| 4e03cb76 | 46 | does not return the actual new standard as :ref:`VIDIOC_G_STD <VIDIOC_G_STD>` does. When |
| 5377d91f MH |
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` |
| 5377d91f MH |
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 | |
| 2212ff25 | 64 | The :ref:`VIDIOC_S_STD <VIDIOC_G_STD>` parameter was unsuitable. |
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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 | .. ------------------------------------------------------------------------------ |