SLEEP(3)
NAME
sleep − suspend execution for interval
USAGE
sleep(seconds) unsigned seconds;
DESCRIPTION
Sleep suspends the current process from execution for the prescribed number of seconds. The actual suspension time may be up to 1 second less than that requested, since scheduled wakeups occur at fixed 1-second intervals, which may be further extended by an arbitrary amount because of other system activity.
The routine is implemented by setting an interval timer and pausing until it times out. The previous state of this timer is saved and restored. If the sleep interval requested exceeds the time remaining on the previous timer, the process sleeps only until that timer times out (the signal is sent 1 second later).