C++ multiple definition error

Question

Starting with sth's answer to this question:

• http://stackoverflow.com/questions/3023760/c-template-specialization

I was wondering how to resolve multiple definition errors if the following code is put in a header file included multiple times by different .cc files and linked together:

template <typename T>
class C {
   static const int K;
   static ostream& print(ostream& os, const T& t) { return os << t;}
};

// general case
template <typename T>
const int C<T>::K = 1;

// specialization
template <>
const int C<int>::K = 2;

Answer 1

Move specialization into one of the .cc files. Leave template version in header.

Answer 2

Depending on the platform, you could surround it by a #ifdef or a something like #pragma once

Answer 3

The only thing I can think of is that you're defining the K variable for all types before any specialization, and so when the compiler would get to the <int> specialization, the variable definition would already exist..

So, if that is the case, you'll want to move the specialization for C<int>::K to before C<T>::K