Path: utzoo!mnetor!tmsoft!torsqnt!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!mcsun!ukc!axion!micromuse!peter
From: peter@micromuse.co.uk (Peter Galbavy)
Newsgroups: comp.lang.c++
Subject: Re: Derived* -> Base* conversion under public/private MI
Message-ID: <1991Feb13.085612.19613@micromuse.co.uk>
Date: 13 Feb 91 08:56:12 GMT
References: <64530@brunix.UUCP>
Organization: Same Planet, Different World, London
Lines: 49

In article <64530@brunix.UUCP> sdm@cs.brown.edu (Scott Meyers) writes:
>
>The ARM says (p. 36) 
>
>     A pointer to a class may be converted to a pointer to an accessible
>     base class of that class provided the conversion is unambiguous;  a
>     base class is accessible if its public members are accessible.
>
>This doesn't help much.  In the above example, Base's public members are
>accessible through one path, inaccessible through the other.  Because Base
>is a virtual base class, ambiguity is not a problem here.
>

I hope I am getting this right - but also the ARM says on page 117 (in
the UK at least - page 36 matches):

---- BOT ----
11.7 Multiple Access

If a name can be reached by several paths through a multiple
inheritance graph, the access is that of the path that gives most
access. For example,

	class W { public: void f(); };
	class A : private virtual W { };
	class B : public virtual W { };
	class C : public A, public B {
		void f() { W::f(); }	// ok
	};

Since W::f() is available to C::f() along the public path through B,
access is legal.
---- EOT ---- All typos are mine ----

I hope that is the right answer to the right question :-) I am still
VERY new to C++ (as far as I am concerned anyway).

On another point - can anyone recommmend a good (up to date) book
along the lines of C++ for C hackers ? I do not want C++ from first
principals, what I need is a book that will enlighten me in certain
areas, and leave my misconceptions alone in others :->

Regards,
-- 
Peter Galbavy

Writing at Home, but working for Micromuse Ltd, who don't even know I
am posting, and probably don't care, so this ain't nothing to do with
them... But if you must, call me daytime on +44 71 352 7774. **BEEP**