Transcription: Like objects of build-in type, objects of class type can be declared to be volatile. You may, for example, have a class in which data members are altered by signal handlers or used by I O functions that are mapped into memory. Such access to data members do not appear in the code and the compiler might optimize the code in such a way that these changes are lost. When you declare an object to be volatile, you ask the compiler not to optimize accesses to its data members.