Question

I have question regarding macros. How could I cast through macro a template class to normal class. In example:

#define RUNTIME_CLASS(class_name) ((CRuntimeClass*)(&class##class_name))

template<typename T> A {};

if (RUNTIME_CLASS(A));

I know that this code wouldn’t compile because it will not see template bit. But I don’t understand the actual macro. the return of it looks like (CRuntimeClass*)(&classA)

Why ## concatenate makes class + A ? and how preprocessor understands such notation?

Answer 1

Maybe where you took the macro all the class names are starting with “class” and the macro expects only the second part of the name, what comes after “class”.