Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uwm.edu!ux1.cso.uiuc.edu!ux1.cso.uiuc.edu!uxa.cso.uiuc.edu!jpd00964
From: jpd00964@uxa.cso.uiuc.edu
Newsgroups: comp.object
Subject: Re: "Messaging" (Re: Reentrant code)
Message-ID: <132000003@uxa.cso.uiuc.edu>
Date: 19 Oct 89 09:40:04 GMT
References: <8636@goofy.megatest.UUCP>
Lines: 34
Nf-ID: #R:goofy.megatest.UUCP:8636:uxa.cso.uiuc.edu:132000003:000:1276
Nf-From: uxa.cso.uiuc.edu!jpd00964    Oct 18 14:52:00 1989


/* Written  1:51 pm  Oct 17, 1989 by jnh@ecemwl.ncsu.edu in uxa.cso.uiuc.edu:comp.object */
In article <135300010@p.cs.uiuc.edu> johnson@p.cs.uiuc.edu writes:
>>
>>
>>I said
>>>> There is no essential difference between Smalltalk messages and C++
>>>> virtual functions.
>>
>>psrc@pegasus.ATT.COM said
>>>Well, not really.  
>>and mentioned perform:.
>>
>>I've used Smalltalk heavily for the last four years, and C++ off
>>and on for the last three years.  I still say that there is no
>>practical difference between messages and virtual functions.  One

[much deleted]

Doesn't Smalltalk/Obj C use run time binding and C++ use compile time binding?
If this is the case, which I strongly believe it to be, then it should be
very very easy to see that there is a big difference between them.

If you have a look up table at run time, then you can literally put in any
object you want, at run time, and the run time libraries will find you method.
If you do it at compile time, then you cannot substitute in another object.
QUICK CLARIFICATION---You can substitute objects, but it is limited in C++.
At least it is in all versions I have seen, which is mostly Think C 4.0 on
the Macintosh.

Now, are you saying that you can do run time binding with C++?

Michael Rutman
Softmed