Hi All I've been experimenting with pimpl recently. What I've seen written about the pimpl idiom is that you have an interface class and an implementation class, and in the interface class you put some kind of pointer to the implementation. However, I thought, sometimes you might want that to be a shared pointer. Or an intrusive pointer. Or unique pointer. Or maybe sometimes you might decide not to use pimpl at all. I thought it was a bit silly that you had to make these decisions at the time you create the interface class. I thought it would be nice if you could write the interface independent of how it was going to be connected to the implementation, and then hook them together however you like. So this is what I've done. Basically I've broke things up into three separate parts: (1) Interface (2) Implementation (3) What joins them together (i've created unique_pimpl and shared_pimpl as examples) I've implemented a unique_ptr and shared_ptr pimpl implementations as examples. The idea is that you can basically do this: unique_pimpl<interface, impl>::create(...) or shared_pimpl<interface, impl>::create(...) make_your_own<interface, impl>::create(...) for any interface and implementation you choose. I've included all the code in a question at http://stackoverflow.com/questions/5666442 but it doesn't seem to be getting much attention there, so I thought I'd bring it up on this list. If something like this isn't in Boost, and people like it, with a bit of help I'd be happy to work on it to get it into Boost. Alternatively I'm happy for someone else to Boostify this. I've used a bit of c++0x in the code, gcc 4.4.5 will compile it though. However if I'm just (badly) reinventing the wheel, if someone could direct me to where this has already been done that would be good to. Thanks Clinton