SLEEP(3C)            INTERACTIVE UNIX System            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 rea-
               sons: (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 actu-
               ally slept) in case the caller had an alarm set to go off
               earlier than the end of the requested sleep time, or prema-
               ture 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 previ-
               ous state of the alarm signal is saved and restored.  The
               calling program may have set up an alarm signal before cal-
               ling 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).


















          Rev. C Software Development Set                            Page 1