Static function in template class

Question

I'm trying to create a sort of factory class in a template. I wanted to do something like a pure virtual function, but it needs to be static as I'm using the function to create types.

What I want to happen is when I declare a class, the template calls the static function. The static function is actually declared in the templatised class.

I've got as far as:

class Base
{

};

template<typename T>
class Type : public Base
{
public:
    static void Create()
    {
        mBase = CreateBase();
    }

private:
    static Base* CreateBase();

    static Base* mBase;
};

class MyType : public Type<MyType>
{
private:        
    static Base* CreateBase()
    {
        return new MyType;
    }
};

template<typename T>
Base* Type<T>::mBase = NULL;

void test()
{
    MyType::Create();
}

I get a link time error:

undefined reference to `Type<MyType>::CreateBase()

Answer 1

The CreateBase function is defined in the base type, so just call it:

template<typename T>
class Type : public Base
{
public:
    static void Create()
    {
        mBase = Base::CreateBase();
    }
//...

There is no need to declare another CreateBase in the template.

Answer 2

Found it.

The problem was I wasn't calling the derived class' function.

Here is the fix:

static void Create()
{
    mBase = T::CreateBase();
}