Method isNull

inst/include/Rcpp/Nullable.h:106–109

* Boolean test for NULL * * @throw 'not initialized' if object has not been set */

         * @throw 'not initialized' if object has not been set
         */
        inline bool isNull() const {
            checkIfSet();
            return Rf_isNull(m_sexp);
        }

        /**
         * Boolean test for not NULL