Boost C++ Libraries

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Struct template is_dimensionless<unit< dimensionless_type, System >>

boost::units::is_dimensionless<unit< dimensionless_type, System >> — check if a unit is dimensionless

// In header: <boost/units/is_dimensionless.hpp>

template<typename System> 
struct is_dimensionless<unit< dimensionless_type, System >> {
};