# File lib/childprocess/windows/lib.rb, line 245
        def last_error_message
          errnum = get_last_error
          buf = FFI::MemoryPointer.new :char, 512

          size = format_message(
            FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_ARGUMENT_ARRAY,
            nil, errnum, 0, buf, buf.size, nil
          )

          str = buf.read_string(size).strip
          if errnum == 0
            "Unknown error (Windows says #{str.inspect}, but it did not.)"
          else
            "#{str} (#{errnum})"
          end
        end