alarm(2) -- Linux man page
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 process in
seconds
seconds.
If
seconds
is zero, no new
alarm
is scheduled.
In any event any previously set
alarm
is cancelled.
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.
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.
CONFORMING TO
SVr4, SVID, POSIX, X/OPEN, BSD 4.3
SEE ALSO
setitimer(2),
signal(2),
sigaction(2),
gettimeofday(2),
select(2),
pause(2),
sleep(3)
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