...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
boost::histogram::axis::traits::extent — Returns axis size plus any extra bins for under- and overflow.
// In header: <boost/histogram/axis/traits.hpp> template<typename Axis> index_type extent(const Axis & axis);