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 2013. The current version is 1.89.0.
boost::units::plane_angle_base_dimension — base dimension of plane angle
// In header: <boost/units/physical_dimensions/plane_angle.hpp> struct plane_angle_base_dimension { };