Re: C++ language: Cloneable cl*****

On May 5, 8:10 am, Krzysiek Czaiñski "Czajnik" <1czaj...@[EMAIL PROTECTED]
>
wrote:
> I'm working on a Cloneable concept for C++ cl*****. Here's what I
> think it should be like, however it doesn't compile :?
>
> #include <memory>
>
> class CloneableBase
....
>     virtual CloneableBase* doClone() const = 0;
....
> template < typename Derived >
> class Cloneable : public CloneableBase
....
>     virtual Derived* doClone() const = 0; // COMPILE ERROR

Looks to me like like the compiler has no way of knowing that Derived
is actually a derivate of CloneableBase and eligible as a covariant
return type. Try Cloneable* as the return type instead?

- Marsh


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