Re: [boost] policy-based smart pointers are EVIL! (was: Intrusive smart pointer)

From: Peter Dimov (pdimov_at_[hidden])
Date: 2002-04-19 06:50:06

From: "Dietmar Kuehl" <dietmar_kuehl_at_[hidden]>
> OK, before you start thinking I have gone entirely stupid (which you
> are, of course, free to think anyway), I want to clarify a little bit:
> The problem with policy-based designs is that similar entities with a
> similar intention become incompatible.

You are right. In particular, the problem is that when library A uses
smart_ptr<T, X> and library B uses smart_ptr<T, Y>, the authors of X and Y
must know about each other in order to provide a conversion.

shared_ptr<T>'s custom deallocator support deliberately doesn't use another
template parameter to avoid this possibility.