[Boost-users] problem in returning mpl::list

Hi I am trying to write a meta-function class, receiving a list as argument and returning the reduced list by poping one element from the front. Here is my code struct Poplist {     template<class seq>     struct apply     {         typedef pop_front<seq>::type res;         static const int value = size<seq>::value;     };    }; int main() {       typedef list_c<int,0,1,2,3,4,5> numbers;       cout<<Poplist::apply<numbers>::value<<endl; } And I got the following error example.cpp:20: error: type ‘boost::mpl::pop_front<seq>’ is not derived from type ‘Poplist::apply<seq>’ example.cpp:20: error: expected ‘;’ before ‘res’ Can someone please rectify my code Thanks in advance