I would like to throw exceptions with meaningful explanation ! I thought of using variable arguments worked fine but lately I figured out it's impossible to extend the class in order to implement other exception types. So I figured out using an std::ostreamstring as a an internal buffer to deal with formatting ... but doesn't compile! I guess it has something to deal with copy constructors. Anyhow here is my piece of code:

  class Exception: public std::exception {
public:
  Exception(const char *fmt, ...);
  Exception(const char *fname,
            const char *funcname, int line, const char *fmt, ...);
  //std::ostringstream &Get() { return os_ ; }
  ~Exception() throw();
  virtual const char *what() const throw();


protected:
  char err_msg_[ERRBUFSIZ];
  //std::ostringstream os_;
};

The variable argumens constructor can't be inherited from! this is why I thought of std::ostringstream! Any advice on how to implement such approach ?