Re: [Boost-users] shared_ptr invalid covariant return type

From: Frank Mori Hess (frank.hess_at_[hidden])
Date: 2008-06-24 10:38:32

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On Tuesday 24 June 2008 09:43 am, John wrote:
> This pattern/idiom is well-established:
>
>    struct A {
>        virtual A*  clone () = 0;
>    };
>
>    struct B : public A {
>        virtual B*  clone ();
>    };
>
>
> But the above does not work when the pointers A* and B* are replaced by
> shared_ptr<A> and shared_ptr<B>:
>
>    struct  A {
>       virtual shared_ptr<A> clone () = 0;
>    };
>
>    struct  B : public A {
>       virtual shared_ptr<B> clone ();
>    };
>
>
> Is there a workaround? Another way to solve the same problem? Thanks!

See:

http://lists.boost.org/boost-users/2003/02/2996.php
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