require 'dl/win32'

message_box = Win32API.new("user32",'MessageBoxA', 'ISSI', 'I')

parent  = 0        
message = "Ok?"
title   = "Error!"
style   = 1 # MB_OKCANCEL

retval = message_box.call( parent, message, title, style )

knapp = case retval
        when 1 then "OK" 
        when 2 then "Cancel"
        else "(?)"
        end
puts "Returverdi: #{retval}. Knapp: #{knapp}"