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Diffstat (limited to 'Documentation/userspace-api/media/dvb/video-get-event.rst')
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diff --git a/Documentation/userspace-api/media/dvb/video-get-event.rst b/Documentation/userspace-api/media/dvb/video-get-event.rst new file mode 100644 index 000000000..90382bc36 --- /dev/null +++ b/Documentation/userspace-api/media/dvb/video-get-event.rst @@ -0,0 +1,105 @@ +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later +.. c:namespace:: DTV.video + +.. _VIDEO_GET_EVENT: + +=============== +VIDEO_GET_EVENT +=============== + +Name +---- + +VIDEO_GET_EVENT + +.. attention:: This ioctl is deprecated. + +Synopsis +-------- + +.. c:macro:: VIDEO_GET_EVENT + +``int ioctl(fd, VIDEO_GET_EVENT, struct video_event *ev)`` + +Arguments +--------- + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. row 1 + + - int fd + + - File descriptor returned by a previous call to open(). + + - .. row 2 + + - int request + + - Equals VIDEO_GET_EVENT for this command. + + - .. row 3 + + - struct video_event \*ev + + - Points to the location where the event, if any, is to be stored. + +Description +----------- + +This ioctl is for Digital TV devices only. To get events from a V4L2 decoder +use the V4L2 :ref:`VIDIOC_DQEVENT` ioctl instead. + +This ioctl call returns an event of type video_event if available. If +an event is not available, the behavior depends on whether the device is +in blocking or non-blocking mode. In the latter case, the call fails +immediately with errno set to ``EWOULDBLOCK``. In the former case, the call +blocks until an event becomes available. The standard Linux poll() +and/or select() system calls can be used with the device file descriptor +to watch for new events. For select(), the file descriptor should be +included in the exceptfds argument, and for poll(), POLLPRI should be +specified as the wake-up condition. Read-only permissions are sufficient +for this ioctl call. + +.. c:type:: video_event + +.. code-block:: c + + struct video_event { + __s32 type; + #define VIDEO_EVENT_SIZE_CHANGED 1 + #define VIDEO_EVENT_FRAME_RATE_CHANGED 2 + #define VIDEO_EVENT_DECODER_STOPPED 3 + #define VIDEO_EVENT_VSYNC 4 + long timestamp; + union { + video_size_t size; + unsigned int frame_rate; /* in frames per 1000sec */ + unsigned char vsync_field; /* unknown/odd/even/progressive */ + } u; + }; + +Return Value +------------ + +On success 0 is returned, on error -1 and the ``errno`` variable is set +appropriately. The generic error codes are described at the +:ref:`Generic Error Codes <gen-errors>` chapter. + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. row 1 + + - ``EWOULDBLOCK`` + + - There is no event pending, and the device is in non-blocking mode. + + - .. row 2 + + - ``EOVERFLOW`` + + - Overflow in event queue - one or more events were lost. |