Hi all, According to the docs <http://www.boost.org/libs/property_map/property_map.html>, "Invoking a property map function on an /invalid/ key results in undefined behavior." True enough; memory is corrupted. How do I prevent this if I am not sure my key is valid. Do I have to keep a list of valid keys separately from my property map? Thanks, -d #include <iostream> #include <map> #include <string> #include <boost/property_map.hpp> template <typename AddressMap> void foo(AddressMap address) { typedef typename boost::property_traits<AddressMap>::value_type value_type; typedef typename boost::property_traits<AddressMap>::key_type key_type; value_type old_address, new_address; key_type fred = "Fred"; old_address = get(address, fred); new_address = "384 Fitzpatrick Street"; put(address, fred, new_address); key_type joe = "Joe"; value_type& joes_address = address[joe]; joes_address = "325 Cushing Avenue"; } int main() { std::map<std::string, std::string> name2address; boost::associative_property_map< std::map<std::string, std::string> > address_map(name2address); name2address.insert(make_pair(std::string("Fred"), std::string("710 West 13th Street"))); name2address.insert(make_pair(std::string("Joe"), std::string("710 West 13th Street"))); foo(address_map); for (std::map<std::string, std::string>::iterator i = name2address.begin(); i != name2address.end(); ++i) std::cout << i->first << ": " << i->second << "\n"; return EXIT_SUCCESS; }