C++, #ifdef question
Not coding in C++ right now but a question came up when I have a question in C#. Hope experts here can easily give a anwser.

    Class A{
      #ifdef AFlag
      public void methodA(){...}
      #endif
    }
    
    Class B{
    ...
      A a;
      a.methodA();
    ...
    }
    
    Class C {
    ...
      A a;
      a.methodA();
    ...
    }

If the AFlag is NOT defined anywhere, what will happen? A compile error or no error but the methodA AND those statements calling that method will not be compiled?
thanks
C++, #ifdef question
===

Not coding in C++ right now but a question came up when I have a question in C#. Hope experts here can easily give a anwser.

    Class A{
      #ifdef AFlag
      public void methodA(){...}
      #endif
    }
    
    Class B{
    ...
      A a;
      a.methodA();
    ...
    }
    
    Class C {
    ...
      A a;
      a.methodA();
    ...
    }

If the AFlag is NOT defined anywhere, what will happen? A compile error or no error but the methodA AND those statements calling that method will not be compiled?
thanks