Re: downcasting smart pointers

From: Eric Ford (eford_at_[hidden])
Date: 2001-05-19 11:51:44

--- In boost_at_y..., "Rainer Deyke" <root_at_r...> wrote:
> The correct value if 'bp' at this point is '0'.  Your function does
not
> mirror this behavior.  The following fixes that problem:
> 
>   template<typename T, typename U>
>   inline shared_ptr<T>& sp_dynamic_cast(const shared_ptr<U>& a)
>   {
>     if (dynamic_cast<T *>(a.get()) {
>       return *(shared_ptr<T>*)&a;
>     }
>     return shared_ptr<T>(0);
>   }

Agreed about the returning 0.  But isn't there a problem here with
returning a temporary?  I changed ito to inline shared_ptr<T>&
sp_dynamic_cast(const shared_ptr<U>& a)

E