#!/usr/bin/perl
use strict;
use warnings;

my $LINUX;
my $WINDOWS;

BEGIN{
    if ($^O eq 'linux') { $LINUX=1; }
    elsif ($^O eq 'MSWin32') { $WINDOWS=1; }
}

use if ($WINDOWS), 'Win32::TieRegistry' => (Delimiter => '/');

if ($WINDOWS) {
    my $mykey=$Registry->{'HKEY_CURRENT_USER/Control Panel/Desktop/WindowMetrics'};
    my $wdpi=hex($mykey->{'AppliedDPI'}) .'dpi / ';
}