From: Maarten Kronenburg (M.Kronenburg_at_[hidden])
Date: 2006-05-26 07:30:58
See my reply to Gerhard.
"Martin Bonner" <martin.bonner_at_[hidden]> wrote in message
> Gerhard Wesp Sent:
> > On Thu, May 25, 2006 at 04:41:32PM +0200, Maarten Kronenburg wrote:
> >> Users can implement an unsigned_integer by deriving from
> >> integer, but this will not give any performance gain.
> > This would violate Item 32 in Effective C++, 3rd ed. by Scott Meyers:
> > Make sure public inheritance models "is-a".
> I agree it's not a good idea.
> > I suggest deriving from integer be disallowed in the TR2 proposal.
> ... however I don't think that is. If C++ had "final", then it could be
> compile time checked. As it is, I don't think TR2 could do more than
> make it undefined behaviour. We really don't want more undefined
> behaviour in C++ if we can avoid it. What is more, deriving from
> integer would actually work on all implementations (as far as public
> inheritance which doesn't model "is-a" works).
> Martin Bonner
> Pi Technology, Milton Hall, Ely Road, Milton, Cambridge, CB4 6WZ,
> ENGLAND Tel: +44 (0)1223 203894
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