Hi Lars, I used nabble.com to pre-format the message, I guess that the pre-formatting is corrupted when sent out to end user's of the list. ... The gist of the problem is that the following template does not compile without the "using namespace std" statement: template <class T> struct MapZipHelperImpl { typedef typename boost::tuple< const T&, const T& > iter_value_type; void operator()( const iter_value_type& iter_value ) { using namespace std; // without this the next line does not compile! typename T::first_type val = iter_value.get<0>().first ; } }; The error is: error: expected primary-expression before ‘)’ token I believe that the "using namespace std;" statement should not be necessary. Is it possible that a header file is missing a std:: qualification and in-advertantly depending on client code to include the "using namespace std;" statement? It took a t of effort to simplify the code that was causing the problem and produce a minimal example. -- View this message in context: http://boost.2283326.n4.nabble.com/zip-iterator-hpp-boost-tuple-requires-a-u... Sent from the Boost - Users mailing list archive at Nabble.com.