Hello, I'm not sure this is specific about boost::array... I apologize if it is not boost specific. I have this code http://codepad.org/h9uFoI1I This compiles under g++4.0 1. I find it strange that it does given that EntryType is a __private__ type inside C. 2. It doesn't do what I expect: my operator< is defined in std namespace but is never called (i did this because with std::pair comes < operators frm the std namespace) I don't want to define operator< for all pairs, just for contexts (member functions of C) which use EntryType. Is this because I typedef EntryType? rds,