This ioctl is deprecated.
File descriptor returned by
Points to the location where the event, if any, is to be stored.
This ioctl call returns a frontend 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.
18.104.22.168.5. Return Value¶
On success 0 is returned.
On error -1 is returned, and the
errno variable is set
There is no event pending, and the device is in non-blocking mode.
Overflow in event queue - one or more events were lost.
Generic error codes are described at the Generic Error Codes chapter.