[Boost-users] [Units] How to use units from different systems

I am trying to use the boost::units library for the first time. I'm able to use the SI system. However, I would like to use units from different systems. Particularly, I would like to be able to write: quantitysi::length L = 3.0 * us::inch + 0.50 * si::meter; The library comes with a us::inch_base_unit. But I don't know how to create a us::inch unit. Any help is appreciated. Juan José