in reply to Re: Should I use threads? Perl/DHCP/Radius
in thread Should I use threads? Perl/DHCP/Radius

The only thing I would add, to yours and BrowserUk's solutions, would be to add an eventloop system in your main program, which can utilize timers to check shared variables on a regular schedule, and do what needs to be done.

This is completely and utterly useless advice. There is absolutely no advantage to using an event loop in the main thread for this.

If there was a requirement to "have the timer in the main program loop do periodic checking of the hash.", that is trivial: 

my @maclist = qw (
    7D:6D:62:C6:B4:3D 01:12:79:3E:14:2E 80:27:E4:EA:60:74
    E8:06:88:7F:8C:83 01:26:08:E8:B6:5D 34:15:9E:5D:E6:49
    03:1E:64:CE:25:88 01:0C:29:3F:67:1B 01:22:69:76:5D:F4
    64:B9:E8:10:BF:20 01:1D:FE:D4:7F:E0
);

my @threads;

foreach my $mac (@maclist){
    push @threads, threads->create( \&doit, $mac );
}

while( sleep 1 ) {
   ## check %clients and do things.
}

$_->join for @threads;

[download]

Recommending the addition of huge, monocultural behemoths like POE or GTK2+glib solely to respond to artificial events generated by a timer is asinine. Like hiring a chainsaw to trim your toenails.

You seem to be suffering from the 'When you have a lumphammer' syndrome.

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.
RIP an inspiration; A true Folk's Guy

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Re^3: Should I use threads? Perl/DHCP/Radius
by zentara (Cardinal) on Aug 24, 2010 at 12:03 UTC
    I respect your aversion to using timers or the fileevent/select methods of eventloop toolkits, but once you learn to use them, they allow much more flexibility in design. Those 
     
while( sleep 1){  do complex hash checking logic  }

    [download]
    loops can get very cumbersome as the complexity of the hash checking increases. Timers and fileevents make things easier. Also, Glib is only a 260k download, less than most of the pictures you download now-a-days. Glib also works on Win32 and Linux type systems. Glib is the basic class of the Firefox browser out there. Are you suggesting Firefox should use while loops instead?

    Maybe you just an old dog, who is averse to learning "new tricks"? :-)

    I'm not really a human, but I play one on earth.
    Old Perl Programmer Haiku flash japh
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[d/l]
      I respect your aversion to using timers or the fileevent/select methods of eventloop toolkits, but once you learn to use them, they allow much more flexibility in design.

      I already know how to use them. I was writing event-driven applications for Optical Mark Readers 25 years ago. And event-driven data transfer applications for racks of hand-held terminals 15 years ago.

      And I also know what a pain they are to tune each time the software has to be moved to a different hardware configuration. And how much simpler life became when I could ditch those fussy, fragile event loops that forever need re-tuning and are a nightmare to debug. In favour of writing nice, straight forward linear code, testing and debugging it as a single-threaded app, and then just running multiple copies each in its own thread.

      Timers and fileevents make things easier.

      Sorry, but that is rubbish. You dream up and code some extension to the OPs scenario with events and I'll demonstrate it is easier with threads.

      Maybe you just an old dog, who is averse to learning "new tricks"?

      Not at all. You've just rediscovered an old bone of mine that I've long since discarded as chewed out :)

      Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
      "Science is about questioning the status quo. Questioning authority".
      In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]
        To each their own.

        I'm sure the OP will soon discover the value of eventloop systems all on his own, regardless of what you or I say.

        I'm not really a human, but I play one on earth.
        Old Perl Programmer Haiku flash japh
[reply]
Re^3: Should I use threads? Perl/DHCP/Radius
by MonkeyMonk (Sexton) on Aug 24, 2010 at 13:42 UTC

    If there was a requirement to "have the timer in the main program loop do periodic checking of the hash.", that is trivial:

    Is what I am doing. But thanks for your advice folks! I am currently figuring out how to synchronize the thread for each MAC with the main thread. Should be interesting!
[reply]
      I am currently figuring out how to synchronize the thread for each MAC with the main thread.

      Could you explain why you need to do that?

[reply]
        I am currently figuring out how to synchronize the thread for each MAC with the main thread.

        The concept is simple. Have a shared hash or array where each thread can write to a scalar. Have a timer ;-) in the main thread loop thru the hash, and make logical descisions for you.

        You have 2 ways of sending messages back from child thread to master thread. One is shared variables, two is thru the fileno's on the open filhandles( which all threads share). You can open a filehandle in the mainthread to listen to with a fileevent method, then have the spawned threads write to that filehandle so that the mainthread can listen for synchronization data.

        Also remember to save the tid's ( thread ids) as you spawn them, so your parent thread can join them later, to destroy them. Just Another Hash Problem. ;-) See Reusable threads demo for enlightenment. P.S. Read the replies for a higher level of enlightenment. :-)

        I'm not really a human, but I play one on earth.
        Old Perl Programmer Haiku ................... flash japh
[reply]

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