#include <typeinfo>
#include <typeindex>
#include <boost/container/flat_map.hpp>
#include <map>


int main()
{
	typedef int handler_t;

	//typedef boost::container::flat_multimap<std::type_index, handler_t> handlers_map_t;
	//typedef boost::container::flat_map<std::type_index, handler_t> handlers_map_t;
	//typedef std::multimap<std::type_index, handler_t> handlers_map_t;
	//typedef std::map<std::type_index, handler_t> handlers_map_t;

	handlers_map_t handlers;

	// this does not compile with flat_multimap, but does compile with flat_map, std::multimap and std::map
	const auto matching = handlers.equal_range(std::type_index(typeid(int)));

	return 0;
}