Phil Bouchard:
template<class P, class D, class A> class sp_counted_impl_pda: public sp_counted_base { ... virtual void destroy() // nothrow { typedef typename A::template rebind< this_type >::other A2;
A2 a2( a_ );
this->~this_type(); a2.deallocate( this, 1 ); // ugh! } };
This is ill-formed code.
I don't think you know what "ill-formed" means.
The way shared_ptr works right now, the pool is going to be copied entirely on to the sp_counted_impl_pda object.
shared_ptr requires that the A argument conforms to the Allocator requirements in the standard (Table 40 in N2691): a1 == a2 bool returns true iff storage allocated from each can be deallocated via the other. operator== shall be reflexive, symmetric, and transitive. X a1(a); post: a1 == a X a(b); post: Y(a) == b, a == X(b) Your example is not an Allocator.