ALARM(3) BSD Library Functions Manual ALARM(3)NAMEalarm — set signal timer alarmLIBRARY
Standard C Library (libc, -lc)
This interface is made obsolete by setitimer(2).
The alarm() function sets a timer to deliver the signal SIGALRM to the
calling process after the specified number of seconds. If an alarm has
already been set with alarm() but has not been delivered, another call to
alarm() will supersede the prior call. The request alarm(0) voids the
current alarm and the signal SIGALRM will not be delivered.
Due to setitimer(2) restriction the maximum number of seconds allowed is
The return value of alarm() is the amount of time left on the timer from
a previous call to alarm(). If no alarm is currently set, the return
value is 0.
SEE ALSOsetitimer(2), sigaction(2), sigpause(2), sigvec(2), signal(3), sleep(3),
An alarm() function appeared in Version 7 AT&T UNIX.
BSD April 19, 1994 BSD