Why compile error with enable_if

Question

Why this does not compile with gcc48 and clang32?

#include 

template  
struct S {

    template 
    typename         


        

Answer 1

Because you use enable_if without using the template parameter T in your function templates. If you want to specialize for when the struct S has a certain template parameter value N, you'll need to use class template specialization.

template  
struct S {  };

template 
struct S::type>
{
  ....
};