It would be really nice if "TR2" would provide enum thread_safety { unsafe, basic }; // strong aside for a moment template<typename numeric, thread_safety scheme_thread_safety> class refcount; (or something like that) and also provide "thread-unsafe" shared_ptr in addition to the current one with its "basic" thread-safety. http://groups.google.de/groups?selm=3F1F26CC.4125AE8B%40web.de Note that in the case of immutable managed objects, "use_count_. decrement()" can be replaced by msync::none version (decrement() is a shortcut for decrement(msync::acq, msync::rel) but increments are all "naked"). Msync on self_count_ can be relaxed a bit as well. This can make quite a difference in performance. (E.g. on the upcoming Xbox... PS3 aside for a moment ;-) ) regards, alexander.