    # File lib/ffi/tools/const_generator.rb, line 85
        def const(name, format = nil, cast = '', ruby_name = nil, converter = nil,
                  &converter_proc)
          format ||= '%d'
          cast ||= ''

          if converter_proc and converter then
            raise ArgumentError, "Supply only converter or converter block"
          end

          converter = converter_proc if converter.nil?

          const = Constant.new name, format, cast, ruby_name, converter
          @constants[name.to_s] = const
          return const
        end