Re: [boost] Re: Re: Smart pointers: One more implementation +question

From: David Bradley (dbradley_at_[hidden])
Date: 2003-02-05 21:18:42

Dave Abrahams wrote:

>Actually, shared_ptr magically deals with this problem by instantiating the
>deleter at the point where it takes ownership of its resource.  As long as
>that's on the same side of the DLL boundary where the resource was
>allocated, you're golden.
>
>  
>
That's something I missed in skimming the implementation, it looked as 
though it was done in the header file. I guess I still find myself on 
the side of seeing the benefits of policy based implementation, and 
finding it hard to see the how it makes things more complex, other than 
for people trying to create new smart pointers implementations, which I 
would argue is difficult in itself and prone to more error than creating 
the necessary traits class for a policy based system.

While working on Mozilla one of the cons against using Boost's shared 
pointer was that it incurred additional storage for the counter, and the 
engineers working on Mozilla wanted an intrusive implementation where 
the counter was stored with the object. It looks like the current 
implementation there is no way other than to create yet another smart 
pointer class to do this. Had Boost gone the policy based route, Mozilla 
would have been able to use such a smart pointer, as it is, Mozilla is 
reinventing the wheel instead of using Boost.

David Bradley