definition StreamLogObserver(const StreamLogObserver &) declaration definition StreamLogObserver(ostream &) declaration definition onNewMessage(const string &,const string &,const int &,const MessageImportance &,const time_t &) declaration definition operator =(const StreamLogObserver &) declaration ~StreamLogObserver() declaration definition StreamLogObserver LogObserver true true inheritance Observer true true inheritance ostream true false has by reference pass by reference pass by reference string true false pass by reference pass by reference pass by reference pass by reference time_t true false pass by reference pass by reference