Re: [Boost-users] Boost::program_optiions - Defining The Config File As A Cmdline Parameter

From: Adam Hartshorne (adam_at_[hidden])
Date: 2006-04-25 06:49:30

Here the is full code example I have adapted from the aforementioned 
given example. The error message thrown is

Unhandled exception at 0x7c81eb33 in Test.exe: Microsoft C++ exception: 
boost::bad_any_cast @ 0x0013f63c.

If I comment out the two lines,
        ifstream ifs("multiple_sources.cfg");
        store(parse_config_file(ifs, config_file_options), vm);
everything works fine.

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

#include <fstream>
#include <iostream>
#include <iterator>
using namespace std;

int main(int ac, char* av[])
{
        int compLevel = 0 ;
        string inputFileName ;

int opt;

         // Declare a group of options that will be
         // allowed only on command line
         po::options_description generic("Generic options");
         generic.add_options()
             ("version,v", "print version string")
             ("help", "produce help message")
             ;

         // Declare a group of options that will be
         // allowed both on command line and in
         // config file
         po::options_description config("Configuration");
         config.add_options()
                        ("input-file", po::value<string>(), "input file")
             ("optimization", po::value<int>(&opt)->default_value(10),
                   "optimization level")
             ("include-path,I",
                  po::value< vector<string> >()->composing(),
                  "include path")
             ;

         // Hidden options, will be allowed both on command line and
         // in config file, but will not be shown to the user.
         //po::options_description hidden("Hidden options");
         //hidden.add_options()
         //    ("input-file", po::value<string>(), "input file")
         //    ;

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

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

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

     if (vm.count("help")) {
             cout << visible << "\n";
             return 0;
         }

        if (vm.count("input-file"))
         {
             cout << "Input file is: "
                  << vm["input-file"].as<string>() << "\n";

                ifstream ifs("multiple_sources.cfg");
                store(parse_config_file(ifs, config_file_options), vm);
                //notify(vm);

         }

        if (vm.count("include-path"))
         {
             cout << "Include paths are: "
                  << vm["include-path"].as<string>() << "\n";
         }

        cout << "Optimization level is " << opt << "\n";

     return 0;
}