Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!wasatch!cs.utexas.edu!tut.cis.ohio-state.edu!rutgers!att!ulysses!andante!alice!ark
From: ark@alice.UUCP (Andrew Koenig)
Newsgroups: comp.lang.c++
Subject: Re: overloading operators on pointers to a class
Message-ID: <9340@alice.UUCP>
Date: 10 May 89 19:14:09 GMT
References: <8905091935.AA26577@AENEAS.MIT.EDU>
Organization: AT&T Bell Laboratories, Liberty Corner NJ
Lines: 24

In article <8905091935.AA26577@AENEAS.MIT.EDU>, FISK@BOWDOIN.BITNET writes:

> I would like to overload an operator that is defined on pointers
> to a class.  Here is what I would like to do.  Is this possible?

> struct M { ... };
> typedef struct M* P;
> P a,b,c;
> a = b+c   // the "+" should be something like P::operator+(P,P)

No.

An overloaded operator must have at least one operand that is
a class (not just a pointer to a class).  This is to prevent
you from changing the meaning of built-in operators.

If you really want to do something like that, you can (in C++ 2.0):
define a class called, say Mptr and define Mptr::operator->().
Then you can use an Mptr pretty much as if it were a pointer,
but you can overload functions based on it, give it a constructor
and destructor, and so on.
-- 
				--Andrew Koenig
				  ark@europa.att.com