Dear all I have question. to the type of object stored in variables_map. In the example multiple_sources.cpp There is line: config.add_options() //... ("include-path,I", po::value< vector<string> >()->composing(), "include path") ; But independently of the case all time result vector has size = 1, so in fact above is equivalent: config.add_options() //... ("include-path,I", po::value< string >()->composing(), "include path") ; And still there is some parsing job to do. How can it be improved? I have tested this example using config file like below: # # Comment out this line to use hard-coded default value of 10 # optimization = 1 include-path = /opt /usr /home/ Regards. -- |\/\/|   Seweryn Habdank-Wojewódzki `\/\/'