...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
boost::units::get_system<absolute< Unit >> — Get the system of an absolute unit.
// In header: <boost/units/get_system.hpp> template<typename Unit> struct get_system<absolute< Unit >> { // types typedef get_system< Unit >::type type; };