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, any pending alarm is canceled.

       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

       This  page  is  part  of  release 3.54 of the Linux man-pages project.  A description of the project, and
       information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.