SLEEP(3C)                            SysV                            SLEEP(3C)



NAME
     sleep - suspend execution for interval

SYNOPSIS
     unsigned sleep (seconds)
     unsigned seconds;

DESCRIPTION
     The current process is suspended from execution for the number of seconds
     specified by the argument.  The actual suspension time may be less than
     that requested for two reasons: (1) Because scheduled wakeups occur at
     fixed 1-second intervals, (on the second, according to an internal clock)
     and (2) because any caught signal will terminate the sleep following
     execution of that signal's catching routine.  Also, the suspension time
     may be longer than requested by an arbitrary amount due to the scheduling
     of other activity in the system.  The value returned by sleep will be the
     "unslept" amount (the requested time minus the time actually slept) in
     case the caller had an alarm set to go off earlier than the end of the
     requested sleep time, or premature arousal due to another caught signal.

     The routine is implemented by setting an alarm signal and pausing until
     it (or some other signal) occurs.  The previous state of the alarm signal
     is saved and restored.  The calling program may have set up an alarm
     signal before calling sleep.  If the sleep time exceeds the time till
     such alarm signal, the process sleeps only until the alarm signal would
     have occurred.  The caller's alarm catch routine is executed just before
     the sleep routine returns.  But if the sleep time is less than the time
     till such alarm, the prior alarm time is reset to go off at the same time
     it would have without the intervening sleep.

SEE ALSO
     alarm(2), pause(2), signal(2).