A missing vtable usually means the first non-inline virtual member function has no definition

Question

I am pretty sure this question is duplicate, but my code is different here, the following is my code. It fails with a \"Undefined symbols\" error, not sure whats missing.

Answer 1

Parent::~Parent() is not defined.

You can put the definition directly into the class definition:

class Parent {
   public :
     virtual int func () = 0;
     virtual ~Parent() {};
 };

Or define it separately. Or, since C++11, write virtual ~Parent() = default;.

In any case, a destructor needs a definition.