[Valmont]

Yes, all you need to do is to pass an identifier of the enum type:

#include <iostream>

using namespace std;

enum MyEnum
{
  NIL, ONE, TWO, THREE
};

ostream& operator<<(ostream& os, const MyEnum& me)
{
  if(me == ONE)
  return os<<1;
  //etcetera
}

int main()
{
  MyEnum theEnum;
  cout<<ONE<<endl;

  cin.get();
  return 0;
}