Re: [boost] [interest] rich-typed smart pointers

Subject: Re: [boost] [interest] rich-typed smart pointers
From: Julian Gonggrijp (j.gonggrijp_at_[hidden])
Date: 2013-10-05 17:26:09

Larry Evans wrote:

>> https://github.com/jgonggrijp/rich-typed-pointers
> [snip]
> If there were a templated owned_ptr CTOR:
> 
>    template<typename Derived>
>    owner_ptr (owner_ptr<Derived> && source) : pointer(source.pointer) {
>        source.pointer = nullptr;
>    }
> 
> wouldn't that eliminate the need for the make_dynamic templated function?
> 
> Just wondering.  I haven't tried it, but I'd guess it would work because
> the ownd_ptr<Derived> could be constructed with the:
> 
>  make<Derived>(t1,t2,...tn)
> 
> and then the templated owned_ptr CTOR would then convert that to the
> base class?

I agree this would be great, but unfortunately it appears it can't be done. 
owner_ptr<Derived> would have to friend-declare owner_ptr<Base>, but it 
can't know in advance that there is a Base. It is not possible to just 
friend-declare owner_ptr<U> for all U, either, because C++ only allows 
complete types as friends (there's no such thing as a templated friend 
declaration).

Thanks for the suggestion though!

-Julian