...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
boost::intrusive::constant_time_size
// In header: <boost/intrusive/options.hpp> template<bool Enabled> struct constant_time_size { // member classes/structs/unions // @ template<class Base> struct pack { static const bool constant_time_size; }; };