osx man page for sleep

SLEEP(3)						   BSD Library Functions Manual 						  SLEEP(3)

NAME
     sleep -- suspend thread execution for an interval measured in seconds

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <unistd.h>

     unsigned int
     sleep(unsigned int seconds);

DESCRIPTION
     The sleep() function suspends execution of the calling thread until either seconds seconds have elapsed or a signal is delivered to the
     thread and its action is to invoke a signal-catching function or to terminate the thread or process.  System activity may lengthen the sleep
     by an indeterminate amount.

     This function is implemented using nanosleep(2) by pausing for seconds seconds or until a signal occurs.  Consequently, in this implementa-
     tion, sleeping has no effect on the state of process timers, and there is no special handling for SIGALRM.

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 requested time minus the time actually slept) in seconds.

SEE ALSO
     nanosleep(2), usleep(3)

STANDARDS
     The sleep() function conforms to ISO/IEC 9945-1:1990 (``POSIX.1'').

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

BSD
								 February 13, 1998							       BSD