SLEEP(3)                  OpenBSD Programmer's Manual                 SLEEP(3)

NAME
     sleep - suspend process execution for interval of seconds

SYNOPSIS
     #include <unistd.h>

     unsigned int
     sleep(unsigned int seconds);

DESCRIPTION
     The sleep() function suspends execution of the calling process until ei-
     ther 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 signal-
     catching 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
     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
     sleep(1), nanosleep(2), select(2), setitimer(2), sigaction(2),
     sigsuspend(2), alarm(3), pause(3), usleep(3)

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

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

OpenBSD 4.5                    October 24, 2008                              1