[Boost-users] [Smart Ptr] intrusive_ptr_add_ref(T * & p)

Looks like it is possible to define intrusive_ptr_add_ref as void intrusive_ptr_add_ref(T * & p) not as void intrusive_ptr_add_ref(T * p) Then, it is possilbe either to increase reference count as usually or to clone the object if it is in non-shareable state. Would this work ? Is it know use case, maintained by Smart Pointers library ?