alarm(3)

NAME

alarm - set signal timer alarm

LIBRARY

Standard C Library (libc, -lc)

SYNOPSIS

#include <unistd.h>
unsigned int
alarm(unsigned int seconds);

DESCRIPTION

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
100000000.

RETURN VALUES

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 ALSO

setitimer(2), sigaction(2), sigpause(2), sigvec(2), sig

nal(3), sleep(3),
ualarm(3), usleep(3)

HISTORY

An alarm() function appeared in Version 7 AT&T UNIX.

BSD April 19, 1994

BSD