NAME    [Toc]    [Back]

     sleep - suspend process execution for interval of seconds

SYNOPSIS    [Toc]    [Back]

     #include <unistd.h>

     unsigned int
     sleep(unsigned int seconds);

DESCRIPTION    [Toc]    [Back]

     The sleep() function suspends execution of the calling  process until either
 the number of seconds specified by seconds have elapsed
or a signal
     is delivered to the calling process and its action is to invoke a signalcatching
  function or to terminate the process.  The suspension time may
     be longer than requested due to the scheduling of other  activity by the
     system.

     This function is implemented using nanosleep(2); it requires
one system
     call each time it is invoked.  A similar but less compatible
function can
     be  obtained  with a single select(2); such a function would
not restart
     after signals, and also does not interfere with  other  uses
of
     setitimer(2)  (not  that  sleep()  interferes  with interval
timers anymore).

RETURN VALUES    [Toc]    [Back]

     If the sleep() function returns because the  requested  time
has elapsed,
     the  value  returned  will be zero.  If the sleep() function
returns due to
     the delivery of a signal, the value returned will be the unslept amount
     (the request time minus the time actually slept) in seconds.

SEE ALSO    [Toc]    [Back]

     nanosleep(2), select(2), setitimer(2), sigaction(2), sigsuspend(2),
     alarm(3), pause(3), usleep(3)

STANDARDS    [Toc]    [Back]

     The  sleep()  function  conforms  to  IEEE  Std  1003.1-1990
(``POSIX'').

HISTORY    [Toc]    [Back]

     A sleep() function appeared in Version 7 AT&T UNIX.

OpenBSD      3.6                           June      4,      1993