void parse_config(int argc, wchar_t* argv[])
    {
        namespace po = boost::program_options;

        po::options_description desc("Allowed options");
        desc.add_options()
            ("dir", po::wvalue<std::wstring>(), "install directory")
            ;

        po::variables_map vm;
        po::store(po::parse_command_line(argc, argv, desc), vm);
        po::notify(vm);

        ... = vm["dir"].as<std::wstring>();