When the virtual member functions of a template class instantiated?

I know that the normal member function of a template class will be instantiated whenever it is used for the first time. But this cannot be done for the 开发者_如何学运维virtual member function as it can be accessed through a base class pointer. Does this mean that virtual member functions will be instantiated as soon as the template class is instantiated? If not, when?

---

14.7.1/9 in C++03:

An implementation shall not implicitly instantiate a function template, a member template, a non-virtual member function, a member class or a static data member of a class template that does not require instantiation. It is unspecified whether or not an implementation implicitly instantiates a virtual member function of a class template if the virtual member function would not otherwise be instantiated.

---

It is implementation defined.

But usually when a template class is instantiated all member for the new class type are generated.

---

According to the C++ Standard 14.6.4.1/4:

If a virtual function is implicitly instantiated, its point of instantiation is immediately following the point of instantiation of its enclosing class template specialization.