exception in c++

exception

class exception {
public:
    exception() throw();
    exception(const exception& rhs) throw();
    exception& operator=(const exception& rhs) throw();
    virtual ~exception() throw();
    virtual const char *what() const throw();
    };

The class serves as the base class for all exceptions thrown by certain expressions and by the Standard C++ library. The C string value returned by what() is left unspecified by the default constructor, but may be defined by the constructors for certain derived classes. None of the member functions throw any exceptions.