What if the default parameter value is defined in code not visible at the call site?

Question

I\'ve found some strange code...

//in file ClassA.h:
class ClassA {
public:
    void Enable( bool enable );
};

//in file ClassA.cpp
#include 

        

Answer 1

Would this only happen when the method is called from within files that include the ClassA.cpp?

That's correct. But note that doing so will almost certainly produce multiple definition errors, so the default is only really available from its point of definition within ClassA.cpp.