As an example, say you have a library with a constant ``++Version++`` member set to ``++1.0++``, and a client application linked to it. This library is then updated and ``++Version++`` is set to ``++2.0++``. Unfortunately, even after the old DLL is replaced by the new one, ``++Version++`` will still be ``++1.0++`` for the client application. In order to see ``++2.0++``, the client application would need to be rebuilt against the new version of the library.
This means that you should use constants to hold values that by definition will never change, such as ``++Zero++``. In practice, those cases are uncommon, and therefore it is generally better to avoid constant members.
