Fellow Monks,

I found a snippet at this node for checking if an instance of a program is running. It seems to work fine, killing a second instance of the program, but I expected the error message "Already executing: $!"; to appear. However, the error message doesn't display. Whats going on? and how can I get the error message to display? 
#!/usr/bin/perl

use Fcntl qw(LOCK_EX LOCK_NB);

flock DATA, LOCK_EX | LOCK_NB or die "Already executing: $!";

my $maxprimes=200; #Stop when you've found this many
my $value=1;
my $count=0;

while ($count < $maxprimes){
        $value++;
        my $composite=0;
OUTER: for (my $i=2; $i<$value; $i++){
       for (my $j=$i; $j<$value; $j++){
             if (($j*$i)==$value){
                   $composite=1;
                   last OUTER;
             }
       }
}
if (! $composite){
    $count++;
    print "$value ";
    }
}

# do not remove this __END__
__END__

[download]
Thanks in advance,
Jonathan

In reply to error message not working by Anonymous Monk

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