ALARM(2) Linux Programmer's Manual ALARM(2)
NAME
alarm - set an alarm clock for delivery of a signal
SYNOPSIS
#include<unistd.h>
unsignedintalarm(unsignedint seconds);
DESCRIPTION
alarm arranges for a SIGALRM signal to be delivered to the process in
seconds seconds.
If seconds is zero, no new alarm is scheduled.
In any event any previously set alarm is cancelled.
RETURNVALUE
alarm returns the number of seconds remaining until any previously
scheduled alarm was due to be delivered, or zero if there was no previ-
ously scheduled alarm.
NOTES
alarm and setitimer share the same timer; calls to one will interfere
with use of the other.
sleep() may be implemented using SIGALRM; mixing calls to alarm() and
sleep() is a bad idea.
Scheduling delays can, as ever, cause the execution of the process to
be delayed by an arbitrary amount of time.
CONFORMINGTO
SVr4, SVID, POSIX, X/OPEN, BSD 4.3
SEEALSO
setitimer(2), signal(2), sigaction(2), gettimeofday(2), select(2),
pause(2), sleep(3)
Linux 1993-07-21 ALARM(2)
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