Sequence of constructor calls in multiple inheritance

Question

I have tried to find a lot that what if only one class is made virtual in multiple inheritance? The behaviour of constructor call is not clear to me in this

Answer 1

The standard says [C++11 section 12.6.2/10] that :

In a non-delegating constructor, initialization proceeds in the following order:

— First, and only for the constructor of the most derived class, virtual base classes are initialized in the order they appear on a depth-first left-to-right traversal of the directed acyclic graph of base classes, where “left-to-right” is the order of appearance of the base classes in the derived class base-specifier-list.

— Then, direct base classes are initialized in declaration order as they appear in the base-specifier-list (regardless of the order of the mem-initializers).

— Then, non-static data members are initialized in the order they were declared in the class definition (again regardless of the order of the mem-initializers).

— Finally, the compound-statement of the constructor body is executed.

So your virtual base classes are always built first... This is really important in the case of virtual base class sharing.