boost::units::autoprefix_mode
// In header: <boost/units/io.hpp> enum autoprefix_mode { autoprefix_none = = 0, autoprefix_engineering = = 4, autoprefix_binary = = 8, autoprefix_mask = = 12 };
automatic scaling and prefix (controlled by value of quantity) a, if any,
autoprefix_engineering
autoprefix_binary
autoprefix_mask