centos man page for alarm

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 pre-
       viously 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 3.53 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/.

Linux								    2013-04-18								  ALARM(2)