Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!apple!rutgers!dptg!att!cbnewsk!ech
From: ech@cbnewsk.ATT.COM (ned.horvath)
Newsgroups: comp.sys.mac.programmer
Subject: Re: C++ for the Mac
Message-ID: <669@cbnewsk.ATT.COM>
Date: 24 Jul 89 19:31:01 GMT
References: <8060@hoptoad.uucp>
Organization: AT&T Bell Laboratories
Lines: 32

Earlier, I wrote:
>Also, the full power of MPW C++ will be available ONLY in applications:
>method dispatching will use global variables, which the brain-damaged
>MPW linker STILL insists must be A5-relative.

From article <8060@hoptoad.uucp>, by tim@hoptoad.uucp (Tim Maroney):
> So?  You can write your own A5 management in code resources under MPW.
> I've done this -- it's pretty easy.  The only thing I couldn't manage
> was initialization to non-zero values (and if I'd spent a few days
> on it, I'm sure I could have cracked that too -- it just didn't seem
> very important).  It's not as easy as under Lightspeed C, granted,
> but it's hardly as close to impossible as you're saying.

Shucks, Tim, I wrote that part of the Aztec linker, including nonzero
initialization.  But when you are talking C++, you ARE talking about
nonzero initialization, and running new() overloads as part of that
initialization.  And when you are talking about method-dispatch tables,
you are talking about data initialized from information provided only
by the compiler and effectively usable by the linker alone.

Yes, I suppose I could ask the MPW linker to create a symbol table, and I
suppose I could write a "post-linker" to put that information into a
resource where my DA's open could find it, and I suppose I might
even be able to track changes in Apple's C++ and MPW naming conventions
and object-file symbol conventions for my own personal use.  Or I suppose
I could write my own linker to do it "right."  Perhaps you could, too.

So I'll rephrase my original statement, thus: unless you are a Maroney-
class guru, and you are prepared to do one shitload of work, you aren't
going to be using virtual methods in non-applications any time soon.

=Ned Horvath=