Whether these examples should be abstract, or based on C++ Standard Library declarations/definitions?
Since the source incompatible changes involves changes in function/class mebmers prototype, or changes in global data/class data members declaration, or changing the place of the some declaration (i.e. moving the declaration from one header file to the another), but requirements of the all of this are stated in C++ Standard and, accordingly, any of these changes are impossible. Farid.