Suppose we've got the following: template<typename T, int N> struct foo { typedef ... type; }; and we want to add MPL lambda support for broken compilers. Should we have #1 or #2? //1 template<typename T, int N> struct foo { BOOST_MPL_AUX_LAMBDA_SUPPORT(1,foo,(T)) typedef ... type; }; //2 template<typename T, int N> struct foo { BOOST_MPL_AUX_LAMBDA_SUPPORT(2,foo,(T,N)) typedef ... type; }; The docs on BOOST_MPL_AUX_LAMBDA_SUPPORT seem not to take into account class templates where some params are non-type. Maybe the macro does not work for them? Thank you, Joaquín M López Muñoz Telefónica, Investigación y Desarrollo