SLEEP

sleep ? Sleep for the specified number of seconds

#include <unistd.h>

unsigned int sleep(unsigned int seconds);

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

Zero if the requested time has elapsed, or the number of seconds left to sleep.

POSIX.1

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

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

signal(2), alarm(2)