ev_pop(S) 6 January 1993 ev_pop(S) Name ev_pop - pop the next event off the queue Syntax cc . . . -levent #include <sys/types.h> #include <sys/param.h> #include <sys/sysmacros.h> #include <sys/page.h> #include <sys/event.h> #include <mouse.h> int ev_pop() Description evpop clears the next event off the queue and returns the number of events that were lost due to queue overrun since the last evpop call. An event queue must have been opened with evinit and evopen. After an application is done with an event, the event is popped off the queue. The queue is of fixed size, so if events are not popped fast enough some might be lost due to overrun. A counter maintains the number of lost events. When evpop 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, evpop returns -1. When evpop is called, the most recent pointer returned by evread must be considered invalid, since that storage may be overwritten by the event driver. Diagnostics evpop 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 evblock(S), evclose(S), evcount(S), evflush(S), evgetdev(S), evgetemask(S), evgindev(S), evinit(S), evopen(S), evread(S), evresume(S), evsetemask(S), evsuspend(S) Standards conformance evpop is not part of any currently supported standard; it is an exten- sion of AT&T System V provided by the Santa Cruz Operation.