Re: Virtual base class
"George" <George@discussions.microsoft.com> wrote in message
news:C339D912-6FE8-433A-8E55-DE334CF7DD95@microsoft.com
I have read the article, very helpful. I do not know why it is
mentioned in Spec "and only for the constructor of the most derived
class as described below"? What does it mean?
The most derived class in your example is D3. It is responsible for
running constructors of virtual base classes. If you were to construct
an instance of, say, D1 standalone, as in "D1 d1;", D1 would be the most
derived class for this object and would be responsible for running B1's
constructor. But when you construct an instance of D3, D1 is not the
most-derived class but is a base class subobject, and is not responsible
for constructing B1 (even though B1 is its base class).
This arrangement guarantees that a virtual base class subobject is
constructed only once (by the most derived class), even if there are
multiple paths leading to it in the inheritance graph.
--
With best wishes,
Igor Tandetnik
With sufficient thrust, pigs fly just fine. However, this is not
necessarily a good idea. It is hard to be sure where they are going to
land, and it could be dangerous sitting under them as they fly
overhead. -- RFC 1925