Question

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 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?

Answer 1

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.