I'm wondering why there is not an efficient built-in way to check whether two things (e.g. a shared_ptr and a weak_ptr, but any combination should work) refer to the same object. In my implementation, I found that a handy thing to have. In changing code that uses a different home-brew smart pointer, I have to achieve this. The only way I see is to first resolve the weak pointer, and then compare the get() from each. That needlessly yoyo's the reference count, which is a horribly expensive atomic operation. I find that in the new C++ standard it refers to a owner_before ordering function, which is a bit more obscure than just comparing the pointers. So I'm wondering why this is not provided. Is there some reason why the feature is obscured, for portability? —John