On Thursday, 31 בMay 2007 12:27, Yosef Meller wrote:
> ציטוט Meron Cohen:
> > ... I'm trying to implement 2 timers in a script....
> On Unix you setitimer (in Time::HiRes)
It doesn't solve Meron's original problem since there's also a
single interval-timer.
Aside from high level wrappers mentioned by others, I'd like to
remind that Unix/Linux alarm(2) system call does two things:
- Set a new alarm timer.
- Returns the time remaining to the expiry of the old timer
(if there was any).
An example:
perl -e '$x=alarm(6); sleep(2); $y=alarm(12); print "x=$x, y=$y\n"'
x=0, y=4
So wrappers that want to implement multiple timers abstraction should
maintain a list of timers (one famous form is in sorted deltas queue)
and use alarm to schedule the next alarm call.
In the $SIG{ALRM} handler the wrapper would schedule the next pending
timer and call some user defined function.
Example (not tested) handler code:
sub our_alarm_handler {
$this = shift @delta_queue;
$func = $this->{FUNC};
$data = $this->{DATA};
$delta = $this->{DELTA};
$next = $delta_queue[0];
alarm $next->{DELTA};
&$func($data);
}
The code to compute the DELTA and insert new timers into the queue
are left as an exercise...
Bye,
--
Oron Peled Voice/Fax: +972-4-8228492
[EMAIL PROTECTED] http://www.actcom.co.il/~oron
ICQ UIN: 16527398
"In fact, one of the saddest but most common conditions in elementary
school computer labs ..., is the children are being trained to use
Word, Excel and PowerPoint. I consider that criminal, because children
should be making things, communicating, exploring, sharing, not
running office automation tools." -- Nicholas Negroponte
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