1 .. SPDX-License-Identifier: GFDL-1.1-no-invari
2 .. c:namespace:: V4L
3
4 .. _VIDIOC_OVERLAY:
5
6 ********************
7 ioctl VIDIOC_OVERLAY
8 ********************
9
10 Name
11 ====
12
13 VIDIOC_OVERLAY - Start or stop video overlay
14
15 Synopsis
16 ========
17
18 .. c:macro:: VIDIOC_OVERLAY
19
20 ``int ioctl(int fd, VIDIOC_OVERLAY, const int
21
22 Arguments
23 =========
24
25 ``fd``
26 File descriptor returned by :c:func:`open(
27
28 ``argp``
29 Pointer to an integer.
30
31 Description
32 ===========
33
34 This ioctl is part of the :ref:`video overlay
35 Applications call :ref:`VIDIOC_OVERLAY` to sta
36 takes a pointer to an integer which must be se
37 application to stop overlay, to one to start.
38
39 Drivers do not support :ref:`VIDIOC_STREAMON`
40 :ref:`VIDIOC_STREAMOFF <VIDIOC_STREAMON>` with
41 ``V4L2_BUF_TYPE_VIDEO_OVERLAY``.
42
43 Return Value
44 ============
45
46 On success 0 is returned, on error -1 and the
47 appropriately. The generic error codes are des
48 :ref:`Generic Error Codes <gen-errors>` chapte
49
50 EINVAL
51 The overlay parameters have not been set u
52 for the necessary steps.
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