SLEEP(3C-SysV)      RISC/os Reference Manual       SLEEP(3C-SysV)



NAME
     sleep - suspend execution for interval

SYNOPSIS
     #include <bsd/sys/types.h>

     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).
















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