Peter Dimov wrote:
This is a bit harder.
class A { private:
WORD m_wData;
private:
A();
public:
static shared_ptr<A> CreateA() { return shared_ptr<A>(new A); }
friend shared_ptr<WORD> GetData( shared_ptr<A> this_ ) { return shared_ptr<WORD>( &this_->m_wData, boost::bind( &shared_ptr<A>::reset, this_ ) ); } };
int main() { shared_ptr<A> pa = A::CreateA(); shared_ptr<WORD> pw = GetData(pa); pa.reset(); std::cout << "*pw: " << *pw << '\n'; }
I'm implementing a mixture of smart_ptr and boost.langbinding libraries. It's in early stage and I don't know yet what it's best for. Candidate number one is a transaction framework. Pointers to objects are smart, of course. They always point to full object and they store dynamic type of the object. Plus, smart pointers hold a pointer to static type. You can clone and swap pointee object. And you can extact a member from it. object_ptr<Y> py(new Y); object_ptr<X> px = py.get_member(&Y::x); // Works even though static types are unknown: object_ptr<void> pvy(py); object_ptr<void> pvx py.get_member(&Y::x); // Other operations: object_ptr<void> copy = pvx.clone(); copy.swap_object(pvx); -- Alexander Nasonov