Hi Monks, I have a rather annoying problem. I have an array that has a list of iso images that needs burning. I have a machine with 3xCDRW in it. I need to start all 3 CDRW simultaneously, toast the first 3 discs, then toast the reaminig discs in the array. Here is my code.please excuse my code, I am not an esteemed parallel programmer
#!/bin/perl -w
use Fcntl qw/F_SETFL O_NONBLOCK O_ASYNC/;
my @fhs;

$SIG{IO} = sub {
  foreach my $fh (@fhs) {
     while (<$fh>) {
        print ("I got $_ from $fh");
     }
  }
};

$SIG{CHLD} = 'DEFAULT';

print ("Saved discs:<br/>\n");
my @sortdiscs = sort(@discs);
my ($cut,$total,$pcntCut);

sub burnEm {
   my ($disc,$writer)=@_;
   my ($pid, $fh);
   print (" $disc is being BURNED\n");
   my @cdrecCmd=(["cdrecord", "-dummy", "-immed", "-eject", "-v", "gra
+cetime=2", "-tao", "dev=$writer", "$distroDirs{$distro}/$disc"]);
  foreach my $cmd (@cdrecCmd) {
     $pid = open($fh,'-|', "@$cmd") or die "Sorry could not fork cdrec
+ord program";
     fcntl $fh, F_SETFL, O_NONBLOCK|O_ASYNC;
     push (@fhs, $fh);
  }
}


while ( @sortdiscs ) {
   print ("\n\tSortDiscs Array:@sortdiscs:\n");
   ($discA,$discB,$discC,@remainingDiscs) = @sortdiscs;
   if (defined $discA) {
      burnEm($discA,"cdrw0");
      if ( defined $discB ) {
         burnEm($discB,"cdrw1");
         if ( defined $discC ) {
            burnEm($discC,"cdrw2");
         }
      }
   }
   @sortdiscs = @remainingDiscs;
}

[download]
Now the fundamental problems are:
1) I have hacked around with this code somewhat and I just can't get it to work.

2) The first 3 CD's don't complete toasting before the child processes starts cutting the next 3. I need to wait for each one to complete before starting the next set.

Nothingmuch helped me quite a bit already, and this is some of his/her code, but I am a bit stumped as to why it will not work as I expect it. I essentially know the reason, but I cannot get there.
Any, and I mean ANY help will be appreciated.
Thanks
Hamish

In reply to forking and ipc by hambo

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