sleep(3C)                                               sleep(3C)



     NAME
          sleep - suspend execution for interval

     SYNOPSIS
          unsigned sleep(seconds)
          unsigned seconds;

     DESCRIPTION
          sleep suspends the current process 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) scheduled wakeups occur at fixed 1-second inter-
          vals, (on the second, according to an internal clock) and
          (2) any caught signal will terminate sleep following execu-
          tion of the signal catching routine.  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 is 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 in case there is 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 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 before the
          alarm signal, the process sleeps only until the alarm signal
          would have occurred and the caller's alarm catch routine is
          executed just before the sleep routine returns.  If the
          sleep time is less than the time before the calling
          program's 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(3).


















     April, 1990                                                     1