Question

我正在使用boost program_options库来处理命令行和配置文件数据，但我不清楚如何从处理过的数据中获取所需的字符串。

如何将get_drinfo函数的program_options命令行参数转换为正确的格式。

//First, the options are declared

po::options_description config("Configuration");
    config.add_options()
        ("IPAddress", po::value< vector<string> >(),"127.0.0.1")
        ("Port", po::value< vector<string> >(),"5000")
         ;
//...

// Attach the config descriptions to the command line and/or config file

    po::options_description cmdline_options;
    cmdline_options.add(config).add(hidden);

    po::options_description config_file_options;
            config_file_options.add(hidden);

    po::options_description visible("Allowed options");
            visible.add(config);

    po::positional_options_description p;
            p.add("input-file", -1);

    po::variables_map vm;
    store(po::command_line_parser(ac, av).
          options(cmdline_options).positional(p).run(), vm);
    notify(vm);

// Use the command line options for IPAddress and Port
// TODO: Load the config file's address and port information
int retval = getaddrinfo(vm["IPAdress"].as< string >(),vm["Port"].as<string>(),    &hint, &list);
// This doesn't work and neither does this
//  int retval = getaddrinfo(vm["IPAdress"].as< vector<string> >(),vm["Port"].as<vector <string> >(),    &hint, &list);

// getaddressinfo

netdb for getaddrinfo的原型是：

extern int getaddrinfo (__const char *__restrict __name,
        __const char *__restrict __service,
        __const struct addrinfo *__restrict __req,
        struct addrinfo **__restrict __pai);

此处提供program_options API的链接：

http://www.boost.org/doc/libs/1_37_0/doc/html/program_options.html

Answer 1

如果所需的参数应该具有类型char *并且您尝试提供string，则编译器将告诉您哪里出错了。阅读该错误消息并尝试理解它。

要从char *获取string，请使用c_str()方法。

使用boost program_options时从命令行获取一个字符串

1 个答案: