I just wrote a quick and dirty test. #include <boost/mpl/vector_c.hpp> namespace mpl = boost::mpl; typedef mpl::vector_c< int, 1,8,0,-2,4 > t1; typedef mpl::vector_c< int, 7,-3,8,0 > t2; // Causes compile error: Passes mpl::void_ type to mpl::plus. //typedef mpl::transform< t1, t2, mpl::plus< _1, _2 > > r; namespace my { template < typename T1, typename T2 > struct plus: mpl::plus< T1, T2 > { }; template < > struct plus< mpl::void_, T > { typedef T type; }; template < > struct plus< T, mpl::void_ > { typedef T type; }; } typedef mpl::transform< t1, t2, my::plus< _1, _2 > > r; Got the following compile error: The class "boost::mpl::vector5<mpl_::integral_c<int, 7>, ..., mpl_::integral_c<int,0>>" has no member "item5". For what it's worth. Eric.

-----Original Message----- From: Lemings, Eric B. (Contr) Sent: Thursday, March 31, 2005 4:10 PM To: 'boost-users@lists.boost.org' Subject: boost::mpl::transform

What is the result type of transform if the algorithm is given two sequences of different sizes?

Thanks, Eric.