[boost] Curiousity question

I would like to ask a design question for any Boost developers or anyone on this mailing list who might care to answer. You are designing or working on a library, perhaps for Boost, perhaps for fun, and part of the design of the library has some public functionality taking a shared pointer as input. You: 1) Use boost::shared_ptr 2) Use std::shared_ptr 3) Use both boost::shared_ptr and std::shared_ptr with the same functionality 4) Use neither, you roll your own shared pointer-like functionality 5) You don't lke shared pointers and use raw pointers instead I really am curious about this. I haven't put any limitation on your library or made any presumption on who your library is for, on purpose. Thanks for anyone answering !