From: David Abrahams (david.abrahams_at_[hidden])
Date: 2002-01-18 16:19:49
----- Original Message -----
From: "Peter Dimov" <pdimov_at_[hidden]>
class hierarchy without a virtual base class destructor?
> Good question.
> Is there a realistic use case where the Derived* -> Base* implicit
> conversion is useful when Base is not polymorphic? ;-)
Absolutely. You can use inheritance for implementation sharing, to reduce
coupling, etc. Maybe the objects aren't even intended to be dynamically
allocated, but linked into a chain on the stack or in global space, for some
reason. The this pointer itself is implicitly converted when calling a base
class function. There are lots of useful designs where non-polymorphic
inheritance can be employed.
The key difference with a non-polymorphic implicit upcast is that pointers
don't, by themselves, manage the lifetimes of their referents. So, there's
no problem with the implicit conversion until you add some meaning to it,
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