use Win32::API;
use Win32::API::Callback;

Win32::API::Struct->typedef( RECT => qw{
                                LONG Left; 
                                LONG Top;
                                LONG Right;
                                LONG Bottom; });

Win32::API::Struct->typedef( MONITORINFO => qw{
                                LONG cbSize; 
                                RECT rcMonitor;
                                RECT rcWork;
                                LONG dwFlags; });

Win32::API->Import('User32', 'EnumDisplayMonitors', 'NPKN', 'N');
Win32::API->Import('User32', 'int GetMonitorInfoA (int hMonitor, LPMONITORINFO lpmi)');

my $MonitorEnumProc = Win32::API::Callback->new(
    sub {
        my( $hMonitor, $hdcMonitor, $lprcMonitor, $dwData) = @_;
        
        my $MI     = Win32::API::Struct->new('MONITORINFO');
        my $R      = Win32::API::Struct->new('RECT');
        $MI->{cbSize} = 40;
        GetMonitorInfoA ($hMonitor, $MI);
        print "Monitor resolution : ",
            $MI->{rcMonitor}->{Right} - $MI->{rcMonitor}->{Left}, ' x ',
            $MI->{rcMonitor}->{Bottom} - $MI->{rcMonitor}->{Top}, "\n";
        return 1;
    },
    "NNPN", "N",
  );

EnumDisplayMonitors ( 0x0, 0x0, $MonitorEnumProc, 0x0  );