Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!bbn!bbn.com!lpringle
From: lpringle@bbn.com (Lewis G. Pringle)
Newsgroups: comp.lang.c++
Subject: Virtual base classes
Keywords: virtual multiple-inheritance
Message-ID: <43245@bbn.COM>
Date: 25 Jul 89 15:08:02 GMT
Sender: news@bbn.COM
Lines: 22


I am a bit confused about calling constructors of virtual base
classes.  According to page 363(bottom) of Lippman, "A base class
specified as virtual must, if it defines any constructors define a
constructor that does not require an argument list..."

I have seen this contradicted elsewhere, but also seen it claimed elsewhere.

Later (page 365) Lippman says "A virtual base class is initialized by its
most derived class."  Now this makes loads of sense, but also seems to make
unnessary the above constraint.

Can anyone clarify if it is really necessary to provide a constructor with no
args (if any) for a virtual base class.  If it is necessary, then why??

					Appropriate Remarks,
							Lewis.
"OS/2: half an operating system for half a computer."

In Real Life:		Lewis Gordon Pringle Jr.
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