Re: [boost] [intrusive_ptr] 2 questions

From: Frank Mori Hess (frank.hess_at_[hidden])
Date: 2008-06-30 09:59:14

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On Friday 27 June 2008 19:00 pm, Gennadiy Rozental wrote:
> 2. Why there is no something like this  provided by the header:
>
> template<typename Derived>
> class intrusive_base {
> protected:
>     intrusive_base() : m_counter( 0 ) {}
>
> private:
>     friend void intrusive_ptr_add_ref( Derived* p ) { ++p->m_counter; }
>     friend void intrusive_ptr_release( Derived* p ) { --p->m_counter; if(
> !p->m_counter ) delete p;  }
>
>     unsigned m_counter;
> };
>
> to be used like this:
>
> class Foo : intrusive_base<Foo>
> {
>  ...
> };

One minor quibble: I think you left out a "public":

class Foo: public intrusive_base<Foo>

otherwise, I get compile errors unless I declare the add_ref/release functions 
as friends to Foo also.
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