Its seems the leaf itself must implement the factory method/weak_this idiom. This initially didn't seem like a good idea in our case since clients write the leaves - we only provide X. But on second thought, perhaps two alternatives are (1) provide a helper template for clients to use when deriving from X to automatically declare the static create()/weak_this
From: "Hickman, Greg" <greg.hickman@lmco.com> [...] pair, Yes, this is what I have done in the CVS with enable_shared_from_this. You could provide template<class T> class enable_shared_from_this { private: weak_ptr<T> weak_this; public: static shared_ptr<T> create() { shared_ptr<T> pt(new T); pt->weak_this = pt; return pt; } shared_ptr<T> shared_from_this() { shared_ptr<T> pt(weak_this); return pt; } }; and let clients define their leaves as class leaf: public enable_shared_from_this<leaf> { // ... };
or (2) use an intrusive reference counting approach for X.
If an intrusive approach ultimately works better for us, what should I do as a boost 1.29.0 user: use counted_base/shared_from_this, or intrusive_ptr (which I admittedly haven't even looked at)?
The counted_base/shared_from_this mechanism will not be present in the next release, so if the above doesn't work for you, it seems that intrusive_ptr would be a better choice.