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ALARM(3)                 BSD Library Functions Manual                 ALARM(3)

NAME
     alarm -- set signal timer alarm

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <unistd.h>

     unsigned
     alarm(unsigned 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), signal(3), sleep(3),
     ualarm(3), usleep(3)

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

BSD                             April 19, 1994                             BSD