Pure Virtual Method Called

Question

EDIT: SOLVED

I\'m working on a multi-threaded project right now where I have a base worker class, with varying worker classes that inherit from it. At r

Answer 1

During initialization classes are only partially constructed. Specifically, constructors have to be executed from the most ancestor class up, so that each derived class'es constructor can safely access its base members.

this means that the vtable of a partially constructed class can not be in its final state - if virtual methods were allowed to call derived classes, those methods would be called before that classes constructor had been called.

Which means that, during construction, pure virtual functions are in fact, pure virtual. Modern c++ compilers are getting better at catching this - but its possible to in many cases "bury" the illegal call in such a way that the compiler doesn't notice the error.

Moral of the story: dont do anything in your constructor that will invoke a virtual function. It just won't do what you expect. Even when it isn't pure.