Hello, by now I have intrusive pass all regression tests locally. There is one modification left, which I'm not sure off, therefore I would like to ask for some advice before committing. All remaining failures are due to the implementation of offset_from_pointer_to_member(): template<class Parent, class Member> inline std::size_t offset_from_pointer_to_member( const Member Parent::* ptr_to_member) { #if ... // 1 return *(const std::ptrdiff_t*)(void*)&ptr_to_member; #elif ... // 2 const Parent * const parent = 0; const char *const member = reinterpret_cast<const char*>(&(parent->*ptr_to_member)); return std::size_t(member - reinterpret_cast<const char*>(parent)); #else ... // 3 return (*(const std::ptrdiff_t*)(void*)&ptr_to_member) - 1; #endif } Currently, variant #3 is chosen, which is obviously wrong. I tried both variant #1 and #2, and both seem to work for CXX. (All tests pass, no crashes.) So which variant should I choose? TIA, Markus