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