compiler happy but undefined symbol in GCC

[roger_onslow]

Can someone please explain how to correct this code which is getting an error when build with gcc

==

template <class T> class Test {
public:
    class SubClass {
    public:
        SubClass() : i(1) {}
        int i;
    };
    static SubClass statics;
};

template<> Test<int> :: SubClass Test<int> :: statics;

int main(int argc, char* const argv[])
{
    int j = Test<int> :: statics.i;
    return 0;
}

==

error message from gcc is

C:\Users\Roger\AppData\Local\Temp/cc0oeaaa.o:bug3.cpp.text+0x17):
undefined reference to `Test<int>::statics'

[roger_onslow]

I've "fixed" it with this 'hack'

==

template <class T> class Test {
public:
	class InnerClass {
	public:
		InnerClass(bool) : i(1) {}
		T i;
	};
	static InnerClass statics;
};

template<> Test<int> :: InnerClass Test<int> :: statics(true);

int main(int argc, char* const argv[])
{
	int j = Test<int> :: statics.i;
	return 0;
}

==

ie added a dummy bool constructor arg to the InnerClass, and then added constructor args to the definition of statics.

A bit ugly, but it works

[phantomotap]

O_o

Soma

template <class T> class Test {
public:
    class SubClass {
    public:
        SubClass() : i(1) {}
        int i;
    };
    static SubClass statics;
};

template <typename T> typename Test<T> :: SubClass Test<T> :: statics;

int main(int argc, char* const argv[])
{
    int j = Test<int> :: statics.i;
    return 0;
}