0001 .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
0002 .. c:namespace:: DTV.video
0003
0004 .. _VIDEO_GET_EVENT:
0005
0006 ===============
0007 VIDEO_GET_EVENT
0008 ===============
0009
0010 Name
0011 ----
0012
0013 VIDEO_GET_EVENT
0014
0015 .. attention:: This ioctl is deprecated.
0016
0017 Synopsis
0018 --------
0019
0020 .. c:macro:: VIDEO_GET_EVENT
0021
0022 ``int ioctl(fd, VIDEO_GET_EVENT, struct video_event *ev)``
0023
0024 Arguments
0025 ---------
0026
0027 .. flat-table::
0028 :header-rows: 0
0029 :stub-columns: 0
0030
0031 - .. row 1
0032
0033 - int fd
0034
0035 - File descriptor returned by a previous call to open().
0036
0037 - .. row 2
0038
0039 - int request
0040
0041 - Equals VIDEO_GET_EVENT for this command.
0042
0043 - .. row 3
0044
0045 - struct video_event \*ev
0046
0047 - Points to the location where the event, if any, is to be stored.
0048
0049 Description
0050 -----------
0051
0052 This ioctl is for Digital TV devices only. To get events from a V4L2 decoder
0053 use the V4L2 :ref:`VIDIOC_DQEVENT` ioctl instead.
0054
0055 This ioctl call returns an event of type video_event if available. If
0056 an event is not available, the behavior depends on whether the device is
0057 in blocking or non-blocking mode. In the latter case, the call fails
0058 immediately with errno set to ``EWOULDBLOCK``. In the former case, the call
0059 blocks until an event becomes available. The standard Linux poll()
0060 and/or select() system calls can be used with the device file descriptor
0061 to watch for new events. For select(), the file descriptor should be
0062 included in the exceptfds argument, and for poll(), POLLPRI should be
0063 specified as the wake-up condition. Read-only permissions are sufficient
0064 for this ioctl call.
0065
0066 .. c:type:: video_event
0067
0068 .. code-block:: c
0069
0070 struct video_event {
0071 __s32 type;
0072 #define VIDEO_EVENT_SIZE_CHANGED 1
0073 #define VIDEO_EVENT_FRAME_RATE_CHANGED 2
0074 #define VIDEO_EVENT_DECODER_STOPPED 3
0075 #define VIDEO_EVENT_VSYNC 4
0076 long timestamp;
0077 union {
0078 video_size_t size;
0079 unsigned int frame_rate; /* in frames per 1000sec */
0080 unsigned char vsync_field; /* unknown/odd/even/progressive */
0081 } u;
0082 };
0083
0084 Return Value
0085 ------------
0086
0087 On success 0 is returned, on error -1 and the ``errno`` variable is set
0088 appropriately. The generic error codes are described at the
0089 :ref:`Generic Error Codes <gen-errors>` chapter.
0090
0091 .. flat-table::
0092 :header-rows: 0
0093 :stub-columns: 0
0094
0095 - .. row 1
0096
0097 - ``EWOULDBLOCK``
0098
0099 - There is no event pending, and the device is in non-blocking mode.
0100
0101 - .. row 2
0102
0103 - ``EOVERFLOW``
0104
0105 - Overflow in event queue - one or more events were lost.
