alarm - schedule a SIGALRM




Arranges to have a SIGALRM delivered to this process after the specified number of seconds have elapsed. (On some machines, unfortunately, the elapsed time may be up to one second less than you specified because of how seconds are counted.) Only one timer may be counting at once. Each call disables the previous timer, and an argument of 0 may be supplied to cancel the previous timer without starting a new one. The returned value is the amount of time remaining on the previous timer.

For delays of finer granularity than one second, you may use Perl's syscall() interface to access setitimer(2) if your system supports it, or else see select below. It is not advised to intermix alarm() and sleep() calls.