USLEEP(3)                            BSD                             USLEEP(3)



NAME
     usleep - suspend execution for interval

SYNOPSIS
     usleep(useconds)
     unsigned useconds;

DESCRIPTION
     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 or
     because of the time spent in processing the call.

     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 a short time later.

     This routine is implemented using setitimer(2); it requires eight system
     calls each time it is invoked.  A similar but less compatible function
     can be obtained with a single select(2); it would not restart after
     signals, but would not interfere with other uses of setitimer.

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