sleep(3) - Linux man page
Name
sleep - sleep for the specified number of secondsSynopsis
#include <unistd.h> unsigned int sleep(unsigned int seconds);
Description
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.Conforming to
POSIX.1-2001.Bugs
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.