...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
boost::interprocess::operator-
// In header: <boost/interprocess/offset_ptr.hpp> template<typename T, typename T2> std::ptrdiff_t operator-(const offset_ptr< T > & pt, const offset_ptr< T2 > & pt2);