NAME

sleep — suspend process execution for interval of 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 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 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.

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

nanosleep(2), usleep(3)

STANDARDS

The sleep() function conforms to IEEE Std 1003.1-1990 (“POSIX.1”).

HISTORY

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