Question

I want to convert a class to a template and this class will have to access some data from typename T. In this case typename T could be an object or pointer to an object. How do I tell within the template if I’m dealing with the pointer or the object?

I can’t use Boost.

Answer 1

You would use a template specialization. First, you would create your template treating the template parameter as a normal type.

template <typename T>
struct Foo {
    T t_;
    Foo () { std::cout << "regular version" << std::endl; }
};

Then, you would specialize the template for when it is a pointer to a type.

template <typename T>
struct Foo<T *> {
    T *t_;
    Foo () { std::cout << "pointer version" << std::endl; }
};

Foo<int> a;
Foo<int *> b;