[boost] Re: [shared_ptr] dealing with shared_ptr and cycles

From: Lorenzo Bettini (bettini_at_[hidden])
Date: 2005-06-06 10:34:13

Jonathan Wakely wrote:
> On Mon, Jun 06, 2005 at 03:58:41PM +0200, Lorenzo Bettini wrote:
> 
> 
>>However, it is not clear to me how to use weak_ptr in this context...
>>
>>can some one provide some clue, please?
> 
> 
> Well, for this context:
> 
>     class C;
> 
>     typedef boost::shared_ptr<C> CP;
>     typedef boost::weak_ptr<C>   WP;
> 
>     class C
>     {
>     private:
>       string s;
>       WP wp;
> 
>     public:
>       C(const string &ss, CP c = CP()) : s(ss), wp(c) {}
>       void set(CP c) { wp = c; }
>       ~C() { cout << "destroying C" << endl; }
>     };
> 
> Then main() would be unchanged.
> 
> That might not work for anything less trivial than your example, since
> you'd need to ensure the shared_ptrs that own the objects are still
> around when you use the weak_ptrs.

indeed, it only works for that simple main: the main problem I had is 
just "ensure the shared_ptrs that own the objects are still
around when you use the weak_ptrs.".

Moreover, I had to deal with mutual dependences, and this makes the 
whole thing worse...