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, 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.

       Alarms created by alarm() are preserved across execve(2) and are not inherited by children
       created via fork(2).

       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 3.74 of the Linux man-pages project.  A  description  of  the
       project,  information  about  reporting  bugs, and the latest version of this page, can be
       found at http://www.kernel.org/doc/man-pages/.



Linux                                       2014-02-23                                   ALARM(2)