#include <iostream>
 
namespace X 
{
  template<typename T> void f(T);
}
 
 
namespace N 
{
  using namespace X;
  enum E { e1 };
  void f(E) 
  {
    std::cout << "N::f(N::E) called\n";
  }
}
 
 
void f(int)
{
  std::cout << "::f(int) called\n";
}
 
 
int main()
{
  ::f(N::e1);  // qualified function name: no ADL
  f(N::e1);    // ordinary lookup finds ::f() and ADL finds N::f(), the latter is preferred.