Path: utzoo!attcan!uunet!tut.cis.ohio-state.edu!att!dptg!ulysses!andante!alice!ark
From: ark@alice.UUCP (Andrew Koenig)
Newsgroups: comp.lang.c++
Subject: Re: Bug in 2.0 with Pass by Reference?
Keywords: bug, cfront 2.0, pass by reference
Message-ID: <10314@alice.UUCP>
Date: 7 Jan 90 22:02:42 GMT
References: <4577@helios.ee.lbl.gov>
Organization: AT&T Bell Laboratories, Liberty Corner NJ
Lines: 22

In article <4577@helios.ee.lbl.gov>, stan@csam.lbl.gov (See-Mong Tan) writes:

> int FSI::pathOpen( char *, StoredObject * &, Class *);

> 	ObjectDictionary * od = 0;
> 	int status = pathOpen( dirname, od, ObjectDictionaryClass );

So od is an ObjectDictionary* and FSI::pathOpen takes a second
argument that is a reference to a StoredObject*.  The two pointer
types StoredObject* and ObjectDictionary* are different types.
It is not possible to bind a StoredObject*& to an ObjectDictionary*
object.  This is true even if ObjectDictionary is derived from
StoredObject -- just because you can bind a StoredObject& to an
ObjectDictionary, that doesn't mean you can bind a StoredObject*&
to an ObjectDictionary*.

One way to see this more clearly is to realize that converting from
ObjectDictionary* to StoredObject* might involve a change in internal
representation in the presence of multiple inheritance.
-- 
				--Andrew Koenig
				  ark@europa.att.com