Hello, I would like to find a way to allow_unregistered program_options, as well as specify cls::unix_style ^ cls::allow_short, where cls is po::command_line_style. The code I've got here doesn't seem to like unrecognized ones: //vis_ are my visible options, vars_ is my variable map. po::store(parse_command_line(argc, argv, vis_, cls::unix_style ^ cls::allow_short), vars_); po::notify(vars_); And then a slight variation with apparently a way to do this (untested), how to specify that cls? // http://stackoverflow.com/questions/10178525/how-to-handle-unsolicited-parame... po::parsed_options parsed_ = po::command_line_parser(argc, argv) .options(vis_).allow_unregistered().run(); Possible? Thank ye... Regards, Michael Powell