Hi all Is that possible to use "unsigned int" type in: config.add_options() ("source-columns,c", po::value< vector<unsigned int> >()->composing(), "List of columns. Can be: 1 2 34 5 2."); If I change "unsigned int" to "std::string" it works good. I mean I can use: -c 1 2 34 5 2 and it works. Regards. -- |\/\/|   Seweryn Habdank-Wojewódzki `\/\/'