Path: utzoo!attcan!uunet!husc6!bloom-beacon!tut.cis.ohio-state.edu!cs.utexas.edu!ut-sally!ut-emx!mybest!bigtex!juniper!bloom!bobd
From: bobd@bloom.UUCP (Bob Donaldson)
Newsgroups: comp.lang.c++
Subject: Re: classes with no data members
Summary: semantics
Keywords: sizeof,empty classes,new
Message-ID: <423@bloom.UUCP>
Date: 22 Jun 88 15:40:42 GMT
References: <464@polari.UUCP> <7943@alice.UUCP> <470@polari.UUCP> <10399@sol.ARPA> <18223@cornell.UUCP>
Lines: 20

In article <18223@cornell.UUCP>, deb@svax.cs.cornell.edu (David Baraff) writes:
> 
> If 'p' and 'q' have no data in their classes (only functions),
> is there any difference between p and q? That is, other than looking
> at the addresses (i.e. p != q), is there anyway to tell p and q apart,
> in a functional or semantic sense? If not, then the above isn't really
> a problem.

If we are getting into semantics, here, it is certainly possible (and
possibly helpful :-)) to distinguish between two DIFFERENT yet otherwise
indistinguishable instances of a type.  The fact that they are different
instances itself may be of some value, even if no difference would arise
from choosing one over the other for a given purpose.
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