명령행 매개변수 해석

#include <stdio.h>
#include <string.h>
#include <getopt.h>

extern char *optarg;
extern int opterr;

int main(int argc,char **argv)
{
        int c,index;
        char host[128] = "127.0.0.1";
        int port = 8000;

        struct option opts[] = {
        {"host",required_argument,NULL,'h'},
        {"port",required_argument,NULL,'p'},
        {0,0,0,0}
        };

        opterr = 0;

        while((c=getopt_long(argc,argv,"h:p:",opts,NULL)) != -1)
        {
                switch(c)
                {
                        case 'h':
                                strcpy(host,optarg);
                                break;
                        case 'p':
                                port = atoi(optarg);
                                break;
                        case '?':
                                printf("Usage : 
"
                                "-h host : set ip address
"
                                "-p port : set port
"
                                );
                                return 1;
                        default:
                                break;
                }
        }

        printf( "ip   : %s
"
                "port : %d
",
                host,port);

        for(index = optind;index < argc;index++)
                printf("Non-option argument %s
",argv[index]);
        return 0;
}

//hello.cpp 
#include <iostream>
#include <string>
#include <boost/program_options.hpp>

using namespace std;
int main(int argc, char* argv[])
{
    using namespace boost::program_options;
    //       
    options_description desc("Allowed options");
    desc.add_options()
        ("help,h", "produce help message")
        ("person,p", value<string>()->default_value("world"), "who")
        ;

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

    if (vm.count("help")) {
        cout << desc;
        return 0;
    }
    cout << "Hello " << vm["person"].as<string>() << endl;
    return 0;
}

>hello 
Hello world

>hello -h
Allowed options:
  -h [ --help ]                produce help message
  -p [ --person ] arg (=world) who

>hello --person len
Hello len

    positional_options_description p;
    p.add("person", -1);
    store(command_line_parser(argc, argv).options(desc).positional(p).run(), vm);

>hello len
Hello len

    ifstream ifs("config.cfg");
    store(parse_config_file(ifs,config),vm);
    notify(vm);

 #include <clpp/parser.hpp>

 #include <iostream>
 
 void help() {
     std::cout << "My program, version 1.0. Common usage is..." << std::endl;
     //
 }
 
 int main( int argc, char* argv[] ) {
     clpp::command_line_parameters_parser parser;
     // Register parameter, without value and without any checking...
     parser.add_parameter( "-h", "--help", help );
     try {
         parser.parse( argc, argv );
         // If user inputs '-h' or '--help' in command line, function 'help()' will be called.
     } catch ( const std::exception& exc ) {
         std::cerr << exc.what() << std::endl;
     }
 
     return 0;
 }