Hello The following piece of code : ____________________ #include<string> #include<map> #include<iostream> #include<iterator> #include typedef std::map map; typedef map::const_iterator const_iterator; struct transformer { typedef std::string result_type; const result_type & operator()(const std::pair & thePair)const { return thePair.first; } }; typedef boost::transform_iterator const_key_iterator; int main() { map m; m["one"]=1; m["two"]=2; const_key_iterator key_iterator(m.begin(),transformer()); // Following 3 lines work fine const std::string &temp = *key_iterator; std::string::const_iterator it_works = temp.begin(); std::cout << *it_works; // Following 2 lines cause crash when // compiled with VS2010 & VS2008 std::string::const_iterator it_fails = key_iterator->begin(); std::cout << *it_fails ; } ________________________________ executes fine when compiled with mingw(gcc 4.5.2) and gcc 4.5.2(Ubuntu 11.04) but crashes when compiled with VS2010 & VS2008. The issue seems to be something about not being allowed to dereference an iterator toa string. Can anyone shed any light on this ? I ensured that language extensions were NOT disabled. Rgds N