Re: [boost] Generic type inferencer function?

Subject: Re: [boost] Generic type inferencer function?
From: Rob Stewart (rob.stewart_at_[hidden])
Date: 2015-12-29 11:47:37

On December 29, 2015 4:38:34 AM EST, "Vicente J. Botet Escriba" <vicente.botet_at_[hidden]> wrote:
> Le 25/12/2015 18:38, Bjorn Reese a écrit :
> >
> > If I have a class T that always must be created as a shared_ptr
> (e.g.
> > because it relies on enable_shared_from_this<T>), then I can ensure
> > that the class can only be constructed via the factory by making the
> > constructor of T private, and let the factory be a friend of T. This
> > works fine if my factory is a static T::create(args...) function,
> but
> > not when using make_shared<T>(args...) because in practice it uses
> > internal helper functions that I cannot make friends of my class.
> >
> I believe there is a place for this kind of classes and to have an 
> associated factory. The question is how to recognize these kind of
> classes.
> 
> My library would only help you to overload make_custom so that you can
> write
> 
>      shared_ptr<T> ptr = make<T>(args...);
> 
> make_custom will replace your T::create(args...).
> 
> Even if the library wouldn't help you a lot (as you need to
> customize), 
> would you prefer make<T>(args...) to T::create(args...)?
> 
> Maybe inheriting T from a specific class could help to identify this 
> kind of classes and so the customization.

Can't his specialization of your customization point be a friend of his class, thereby having access to the private constructor?

Does the customization point specify the return type so he can get his shared_ptr?

___
Rob

(Sent from my portable computation engine)