...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
boost::accumulators::droppable_accumulator
// In header: <boost/accumulators/framework/accumulators/droppable_accumulator.hpp> template<typename Accumulator> struct droppable_accumulator : public boost::accumulators::droppable_accumulator_base< Accumulator > { // construct/copy/destruct template<typename Args> droppable_accumulator(Args const &); };