Greetings: I have uploaded a cleaner version of shifted_ptr including better intrusive containers (intrusive_list & intrusive_stack) stripped from redundant information. The containers were initialy designed for shifted_ptr but proposes an interface that could be extended from ground up. Indeed, in this concept containers have no idea what the element_type is; it only knows about pointers to nodes. The responsability of knowing about the element_type is forwarded to the iterator, usualy using within a loop, which is eventually dereferenced appropriately. Having stricter containers could have been there but this is primaly a tool that is adapted to shifted_ptr and removes a lot of forward declarations because the type needs not be known. Secondly right now I would be happy to learn segfault are detected using shifted_ptr. Please provide simple case scenarios and I will trace the problem. This is not yet multithreaded and compiles fine only on x86: http://www.boost-consulting.com/vault/index.php?action=downloadfile&filename=shifted_ptr.zip&directory=Memory& Regards, -Phil