It's not re-allocating memory each time through the loop. You can test that by doing this:

    my $count = 1;
    while (my $x = $count) {
        print \$x, "\n";
        last if ++$count > 5;
    }
[download]

If you run that, you should get something like:

    SCALAR(0x80e4aa8)
    SCALAR(0x80e4aa8)
    SCALAR(0x80e4aa8)
    SCALAR(0x80e4aa8)
    SCALAR(0x80e4aa8)
[download]

Each time through the loop $x is at the same memory location. So it's not re-allocating memory.

As tilly mentions in his post, Perl does have to do *some* extra things--but re-allocating memory isn't one of them. :)

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