Fully thread-safe shared_ptr implementation

Question

Does anybody know of a fully thread-safe shared_ptr implementation? E.g. boost implementation of shared_ptr is thread-safe for the targets (refcounting

Answer 1

I dont think this so easy, it is not enough to wrap your sh_ptr classes with a CS. It is true that if you maintain one single CS for all shared pointers it can ensure to avoid mutual the access and deletion of sh_ptr objects among different threads. But this would be terrible, one CS object for every shared pointer would be a real bottleneck. It would be suitable if every wrappable new ptr -s have different CS s' but this way we should create our CS dinamically, and ensure the copy ctors of sh_ptr classes to transmit this shared Cs. Now we arrived to the same problem: who quaranties that this Cs ptr is already deleted or not. We can be a little more smarty with volatile m_bReleased flags per instance but this way we cannot stuck the safety gaps between checking the flag and using the shared Cs. I can't see completely safe resolution for this problem. Maybe that terrible global Cs would be the minor bad as killing the app. (sorry for my english)