Simple variadic template function can't instantinate

Question

I\'m aware that sizeof...(Args...) yields the number of types in a C++0x packed template argument list, but I wanted to implement it in terms of other features

Answer 1

Konrad's answer should get you going, but I think the more idiomatic way such things are usually expressed is with static member constants, so I just wanted to present that solution:

#include 

template  struct arg_size;  // no primary definition needed

template  struct arg_size
  : public std::integral_constant::value> { };

template <> struct arg_size<>
  : public std::integral_constant { };

Then you get your argument pack size via arg_size::value.