...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::validation_error
// In header: <boost/program_options/errors.hpp> class validation_error : public boost::program_options::error_with_option_name { public: enum kind_t { multiple_values_not_allowed = 30, at_least_one_value_required, invalid_bool_value, invalid_option_value, invalid_option }; // public member functions validation_error(kind_t, const std::string & = "", const std::string & = "", int = 0); kind_t kind() const; // protected member functions std::string get_template(kind_t); };