Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!cs.utexas.edu!usc!apple!apple.com!chewy
From: chewy@apple.com (Paul Snively)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Multiple Inheritance for HandleObjects in C++
Message-ID: <8940@goofy.Apple.COM>
Date: 30 Jun 90 01:37:25 GMT
References: <15132@reed.UUCP>
Sender: usenet@Apple.COM
Organization: Apple Computer, Inc.
Lines: 33

In article <15132@reed.UUCP> bowman@reed.UUCP (Eric Bowman) writes:
> I've just discovered, to my horror, that you can't create HandleObjects
> with multiple base classes in MPW C++.  Are there any work arounds for 
this?
> Anyone know why this is the case?

Larry Rosenstein and Amanda Walker have already done an excellent job of 
answering the question Eric poses, but I'd like to point out something 
else:

Since Eric is using HandleObjects, he apparently isn't concerned about 
Object Pascal compatibility.  This means that he's probably concerned 
about fragmenting the heap, which standard C++ objects, being based on 
malloc and free, tend to do.

Andy Shebanow, a former engineer here in MacDTS, wrote a very good article 
in "D e v e l o p" describing a class that he created called "PtrObject."  
The idea was to provide all of the functionality of standard C++ but to 
use NewPtr and DisposPtr to manage memory instead of malloc and free.  
Perhaps Eric would benefit from using Andy's PrtObject class.

Just a thought...

__________________________________________________________________________
                                Paul Snively
                      Macintosh Developer Technical Support
                             Apple Computer, Inc.

chewy@apple.com

Just because I work for Apple Computer, Inc. doesn't mean that I believe 
what they believe, or vice-versa.
__________________________________________________________________________