Boost
C++ Libraries
...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
This is an older version of Boost and was released in 2021. The current version is 1.90.0.
boost::units::si::kilogramme_per_cubic_metre
// In header: <boost/units/systems/si/mass_density.hpp> static const mass_density kilogramme_per_cubic_metre;