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@(#)@(#)usleep.3 6.1 (Berkeley) 01/09/86

C 6 usleep - suspend execution for interval

 usleep(useconds)  unsigned useconds; 

The current process is suspended from execution for the number of microseconds specified by the argument. The actual suspension time may be an arbitrary amount longer because of other activity in the system.

The routine is implemented by setting an interval timer and pausing until it occurs. The previous state of this timer is saved and restored. If the sleep time exceeds the time to the expiration of the previous timer, the process sleeps only until the signal would have occurred, and the signal is sent 2 system clock ticks later. .sh BUGS This routine is expensive to use because it is implemented using setitimer (2) and does eight system calls each time it is invoked. It should be implemented using select (2).

setitimer(2), getitimer(2), sigpause(2), ualarm(3), sleep(3), alarm(3)