#!/usr/bin/perl -w
use strict;
use Benchmark;
Benchmark::cmpthese(10_000, {
    'C-style' => sub { for (my $i = 0; $i <= 1000; $i++){ undef } },
    'foreach' => sub { for my $i (0..1000) { undef } }
});
__END__
Benchmark: timing 10000 iterations of C-style, foreach...
   C-style:  5 wallclock secs ( 5.20 usr +  0.00 sys =  5.20 CPU) @ 1923.08/s (n=10000)
   foreach:  4 wallclock secs ( 3.73 usr +  0.00 sys =  3.73 CPU) @ 2680.97/s (n=10000)
        Rate   C-style foreach
C-style 1923/s      --    -28%
foreach 2681/s     39%      --

##</code><code>##

2;0 juerd@ouranos:~$ perl -e'undef christmas'
Segmentation fault
2;139 juerd@ouranos:~$