...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
boost::program_options::unknown_option
// In header: <boost/program_options/errors.hpp> class unknown_option : public boost::program_options::error_with_no_option_name { public: // construct/copy/destruct unknown_option(const std::string & = ""); ~unknown_option(); };