class template instantiation

Question

I just read the wiki article about CRTP, and I\'m a little confused about template instantiation.

According to the wiki,

member function bodi

Answer 1

You seem to be confusing one thing:

Instantiation happens during compilation, not during runtime. Hence you can't say "on which line" a class template or a function template was instantiated.

That said, you're right about the fact that member function templates aren't instantiated together with class templates.

You could observe it in such a case: You have the following files

• template.h (defines class A and function A::foo)
• a.cpp (uses A)
• b.cpp (uses A and A::foo)

Then during compilation of a.cpp, only A would be instantiated. However, during compilation of b.cpp, both would be instantiated.

Because of this, in case A::foo contained some semantically invalid code for a given set of template parameters, you would get compile errors in b.cpp, but not a.cpp.

I hope that clears things up!