template <const char *str> 
class Hoge
{
public:
    const char *GetString() const { return str; }
};

const char String1[] = "Hoge";
extern const char String2[] = "Hoge";

int main()
{
    Hoge<String1> h;
    cout << h.GetString() << endl;

    return 0; 
}

In function 'int main()':
Line 13: error: 'String1' cannot appear in a constant-expression
compilation terminated due to -Wfatal-errors.