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NAME

       alarm - set an alarm clock for delivery of a signal

SYNOPSIS

       #include <unistd.h>

       unsigned int alarm(unsigned int seconds);

DESCRIPTION

       alarm()  arranges  for  a SIGALRM signal to be delivered to the calling
       process in seconds seconds.

       If seconds is zero, no new alarm() is scheduled.

       In any event any previously set alarm() is canceled.

RETURN VALUE

       alarm() returns the number of seconds remaining  until  any  previously
       scheduled  alarm  was  due  to  be  delivered,  or zero if there was no
       previously scheduled alarm.

CONFORMING TO

       SVr4, POSIX.1-2001, 4.3BSD.

NOTES

       alarm() and setitimer(2) share  the  same  timer;  calls  to  one  will
       interfere with use of the other.

       sleep(3)  may be implemented using SIGALRM; mixing calls to alarm() and
       sleep(3) is a bad idea.

       Scheduling delays can, as ever, cause the execution of the  process  to
       be delayed by an arbitrary amount of time.

SEE ALSO

       gettimeofday(2),   pause(2),   select(2),  setitimer(2),  sigaction(2),
       signal(2), sleep(3), time(7)

COLOPHON

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