Re: [boost] intrusive_ptr and overloading not working under VC++ 8

From: David Abrahams (dave_at_[hidden])
Date: 2005-12-10 10:57:25

"art" <art_at_[hidden]> writes:

> Does intrusive_ptr work with overloading on any other compiler?
>
> This is a general problem and as I proposed above to solve the ambiguity you
> have to use SFINE in template constructor of intrusive_ptr/shared pointer.
>
> template< class T2 >
> shared_ptr( const shared_ptr<T2>& s_ptr, typename
> enable_if<is_convertible<T*,T2*>::result, void* >::type = 0)
> {  ... }
>
> I think it should be added to boost smartptr.

That isn't really a complete solution:

  struct Base {};
  struct Derived : Base {};
  struct Bottom : Derived {};

  int f(shared_ptr<Base>);      // #1
  int f(shared_ptr<Derived>);   // #2

  shared_ptr<Bottom> x(new Bottom);
  int y = f(x);                 // Should call #2, but is ambiguous

will still fail, and there's not really any way to make it work.

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com