Jonathan's suggested replacement text says that a pure constraint in a derived virtual class can replace an inherited pure constraint. But this raises a question: can a pure constraint in a derived virtual class replace an inherited constraint that has an implementation? I ran into this same issue recently with pure virtual methods. What happens if a base virtual class provides an implementation for a method, and a derived virtual class declares a pure virtual prototype for that method? My first reaction was that this was an error. An implementation was provided, so this isn't a pure virtual method any more. But there is another way it could be treated. The pure virtual prototype could override and hide the implementation inherited from the base class. Any further derived classes would then have to provide an implementation. This could be useful. It would allow you to provide an implementation to some derived classes, but if it was inappropriate for a subset of the derived classes, you could hide it from those and make them provide one. Steven Sharp sharp@cadence.com -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean.Received on Mon Jun 22 11:03:29 2009
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