// In header: <boost/program_options/errors.hpp>


class invalid_syntax : public boost::program_options::error {
public:

  enum kind_t { long_not_allowed =  30, long_adjacent_not_allowed, 
                short_adjacent_not_allowed, empty_adjacent_parameter, 
                missing_parameter, extra_parameter, unrecognized_line };
  // construct/copy/destruct
  invalid_syntax(const std::string &, kind_t);
  ~invalid_syntax();

  // public member functions
  kind_t kind() const;
  const std::string & tokens() const;

  // protected static functions
  static std::string error_message(kind_t);
};