Boost Exception

namespace
boost
    {
    class
    exception
        {
        public:
    
        virtual char const * diagnostic_information() const throw();    
    
        protected:
    
        exception();
        exception( exception const & x );    
        ~exception();    
        };    
    
    template <class T>
    ---unspecified--- enable_error_info( T const & x );    
    
    template <class T>
    ---unspecified--- enable_current_exception( T const & e );
    }