boost之program_options库，解析命令行参数、读取配置文件

一、命令行解析

tprogram_options解析命令行参数示例代码：

#include <iostream>
using namespace std;

#include <boost/program_options.hpp>
namespace po = boost::program_options;

int main(int argc, char*argv[])
{
    //int level;
    po::options_description desc("Allowed options");
    desc.add_options()
        ("help", "produce help message")
        //("help,h", "produce help message")
        ("compression", po::value<int>(), "set compression level");
        //("compression", po::value<int>(&level)->default_value(1), "set compression level");

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

    if(vm.count("help"))
    {
        cout<<desc<<endl;
        return 1;
    }

    if(vm.count("compression"))
    {
        cout<<"compression level was set to "<<vm["compression"].as<int>()<<"."<<endl;
        //cout<<"compression level: "<<level<<endl;
    }
    else
    {
        cout<<"compression level was not set."<<endl;
    }

    return 0;
}

运行结果：

输入参数：--help

输入参数：--compression 10

二、读取配置文件（Linux、Windows均可）

2.1 代码

#include <fstream>
#include <map>
using namespace std;

#include <boost/program_options.hpp>
using namespace boost;
namespace po = boost::program_options;

#ifdef WIN32
#include "C:Usersgwy8868Desktopfast_dr302fast_dr302globalxtokens.h"
#else
#include "/opt/guowenyan/fast_dr302/global/xtokens.h"
#endif


std::pair<std::string, std::string> at_option_parser(std::string const& s)
{
    if ('@' == s[0])
    {
        return make_pair(std::string("config"), s.substr(1));
    }
    else
    {
        return std::pair<std::string, std::string>();
    }
}

int main(int argc, char*argv[])
{
    //
    string host_ip;
    short  host_port;

    string server_ip;
    short  server_port;

    //
    po::options_description hostoptions("host options");
    hostoptions.add_options()
        ("host_ip,H", po::value<string>(&host_ip), "set db_host")
        ("host_port,P", po::value<short>(&host_port)->default_value(3306), "set db_port");

    po::options_description general("general options");
    general.add_options()
        ("help,h", "produce help message")
        ("server_ip,s", po::value<string>(&server_ip), "set the http_server's ip. e.g. '202.106.0.20'")
        ("server_port,p", po::value<short>(&server_port)->default_value(80), "set the http_server's port. default:80");

    string config_file;
    po::options_description config("config options");
    config.add_options()
        ("config", po::value<string>(&config_file)->default_value("config.conf"),
        "set config file, specified with '@name' too");

    po::options_description all("All options");
    all.add(hostoptions).add(general).add(config);

    po::variables_map vm;
    po::store(po::command_line_parser(argc, argv).options(all).extra_parser(::at_option_parser).run(), vm);

    if (vm.count("help"))
    {
        cout << hostoptions <<endl;
        cout << general << endl;
        cout << config << endl;
        return false;
    }

    if (vm.count("config"))
    {
        string conf_name = vm["config"].as<string>();
        ifstream ifs_config(conf_name.c_str());

        if (! ifs_config)
        {
            cerr << "could not open the configure file" << endl;
            return false;
        }

        stringstream ss_config;
        ss_config << ifs_config.rdbuf();

        global::strings_t args;
        global::separate_tokens(ss_config.str(), args, " 
");
        po::store(po::command_line_parser(args).options(all).run(), vm);
    }
    po::notify(vm);


    //
    cout<<"host_ip: "<<host_ip<<endl;
    cout<<"host_port: "<<host_port<<endl;

    cout<<"server_ip: "<<server_ip<<endl;
    cout<<"server_port: "<<server_port<<endl;

    return 0;
}

2.2 配置文件

config.conf：

config2.conf：

2.3 输出结果