According to the Learning Perl book, truncating an array does not recover its memory. To feee memory I need to undef the array like this undef(@array). It also says that the memory doesn't always get free because not many operating systems support this. I find this strange as I've never had this problem in other languages.

I'm using Win2K and not much memory gets free when I undef my array. When I run the script below the @array takes ~76,000K in memory when I hit the breakpoint. After undef(@array) gets executed the memory only goes down to ~72,000K. If I continue the loop and watch memory it'll fluctuate between these two numbers.

Is there another way to free the memory? Does anyone else find this behavior strange? I must be missing something, perhaps some monks can enlighten me.

Thanks.

use strict;
use warnings;
print $$;
my @array;
my $i = 0;
while (1) {
    $array[$i++]= '1234567890';
    if ($i == 1_000_000) {
        undef(@array); #BREAKPOINT HERE
        $i = 0;
    }
}
[download]

UPDATE
The memory is even kept after the array goes out of scope.

use strict;
use warnings;
print "PID: $$\n";
{
    my @array;
    my $i = 0;
    while ($i <= 1_000_000) {

        $array[$i++]= '1234567890';# for([0..1_000_000]);
        if ($i == 1_000_000) {
            undef(@array);
        }
    }
}
print "END\n"; # BREAKPOINT HERE, MEMORY IS STILL NOT FREE
[download]

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