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 ter-
minate 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 implementation,
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
Mac OS X 10.8 - Generated Fri Aug 31 05:27:50 CDT 2012