C++ static template member, one instance for each template type?

Question

Usually static members/objects of one class are the same for each instance of the class having the static member/object. Anyways what about if the static object is part of a

Answer 1

In C++ templates are actually copies of classes. I think in your example there would be one static instance per template instance.

Answer 2

A<int> and A<float> are two entirely different types, you cannot cast between them safely. Two instances of A<int> will share the same static myObject though.

Answer 3

There are as many static member variables as there are classes and this applies equally to templates. Each separate instantiation of a template class creates only one static member variable. The number of objects of those templated classes is irrelevant.

Answer 4

Static members are different for each diffrent template initialization. This is because each template initialization is a different class that is generated by the compiler the first time it encounters that specific initialization of the template.

The fact that static member variables are different is shown by this code:

#include <iostream>

template <class T> class Foo {
  public:
    static int bar;
};

template <class T>
int Foo<T>::bar;

int main(int argc, char* argv[]) {
  Foo<int>::bar = 1;
  Foo<char>::bar = 2;

  std::cout << Foo<int>::bar  << "," << Foo<char>::bar;
}

Which results in

1,2