Hi all, I've used mutable_queue with basic types (double and int) with no problem. Now I trying to do it with my own type: typedef MyObject entry_t; typedef vector<entry_t> storage_t; typedef MySortingCriterion comp_t; typedef boost::identity_property_map prop_map_t; typedef boost::mutable_queue<entry_t, storage_t, comp_t, prop_map_t> queue_t; queue_t Q(100, comp_t(), prop_map_t()); The definition compiles ok but when I perform an operation such Q.push(obj) //MyObject obj The following errors appear: C:\boost\boost_1_42_0/boost/property_map/property_map.hpp: In function 'Reference boost::get(const boost::put_get_helper<Reference, PropertyMap>&, const K&) [with PropertyMap = boost::typed_identity_property_map<unsigned int>, Reference = unsigned int, K = boost::shared_ptr<CAStarNode>]': C:\boost\boost_1_42_0/boost/pending/mutable_queue.hpp:94: instantiated from 'void boost::mutable_queue<IndexedType, RandomAccessContainer, Comp, ID>::push(const IndexedType&) [with IndexedType = boost::shared_ptr<CAStarNode>, RandomAccessContainer = std::vector<boost::shared_ptr<CAStarNode>, std::allocator<boost::shared_ptr<CAStarNode> > >, Comp = astarnode::SGreater, ID = boost::typed_identity_property_map<unsigned int>]' ..\CAStar.cpp:62: instantiated from here C:\boost\boost_1_42_0/boost/property_map/property_map.hpp:318: error: no match for 'operator[]' in '(const boost::typed_identity_property_map<unsigned int>&)((const boost::typed_identity_property_map<unsigned int>*)(& pa))[k]' C:\boost\boost_1_42_0/boost/property_map/property_map.hpp:553: note: candidates are: T boost::typed_identity_property_map<T>::operator[](const T&) const [with T = unsigned int] It seems the problem is with property_map. Anyone knows how to solve it?? Thank you very much, Cheers, Emili