EV_POP(S) UNIX System V EV_POP(S)
Name
ev_pop - pop the next event off the queue
Syntax
#include <types.h>
#include <param.h>
#include <sysmacros.h>
#include <page.h>
#include <event.h>
#include <mouse.h>
int ev_pop()
Description
ev_pop clears the next event off the queue and returns the
number of events lost due to queue overrun since the last
ev_pop call. An event queue must have been opened with
ev_init(S) and ev_open(S).
After an application is done with an event, the event is
pop'ed off the queue. The queue is of fixed size, so if
events are not pop'ed fast enough some might be lost due to
overrun. A counter maintains the number of lost events.
When ev_pop is called, it clears the top event off of the
queue, clears the counter and returns the number of lost
events. This should always be zero, unless a program stops
reading its event queue. If the queue is empty, ev_pop
returns -1.
When ev_pop is called, the most recent pointer returned by
ev_read must be considered invalid, since that storage may
be overwritten by the event driver.
Diagnostics
ev_pop returns -1 if there is not an open event queue. It
returns -2 if there is nothing to pop because the queue is
empty.
See Also
ev_block(S), ev_close(S), ev_count(S), ev_flush(S),
ev_getdev(S), ev_getemask(S), ev_gindev(S), ev_init(S),
ev_open(S), ev_read(S), ev_resume(S), ev_setemask(S),
ev_suspend(S)
Notes
This routine must be linked in with the -levent linker
option.
(printed 6/20/89)