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ALARM(2)                   Linux Programmer's Manual                  ALARM(2)



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
       This  page  is part of release 3.22 of the Linux man-pages project.  A description of the project, and informa-
       tion about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.



Linux                             2008-06-12                          ALARM(2)