sleep man page

sleep — sleep for the specified number of seconds


#include <unistd.h>

unsigned int sleep(unsigned int seconds);


sleep() makes the calling thread sleep until seconds seconds have elapsed or a signal arrives which is not ignored.

Return Value

Zero if the requested time has elapsed, or the number of seconds left to sleep, if the call was interrupted by a signal handler.


For an explanation of the terms used in this section, see attributes(7).

sleep()Thread safetyMT-Unsafe sig:SIGCHLD/linux

Conforming to

POSIX.1-2001, POSIX.1-2008.


sleep() may be implemented using SIGALRM; mixing calls to alarm(2) and sleep() is a bad idea.

Using longjmp(3) from a signal handler or modifying the handling of SIGALRM while sleeping will cause undefined results.

See Also

sleep(1), alarm(2), nanosleep(2), signal(2), signal(7)

Referenced By

aio(7), alarm(2), clock_nanosleep(2), dnscap(1), dskutil(1), explain(1), explain(3), explain_sleep(3), explain_sleep_or_die(3), getitimer(2), nanosleep(2), pth(3), pthsem(3), signal(7), sleep(1), time(7), ualarm(3), upslog(8), usleep(3).

Explore man page connections for sleep(3).