Path: utzoo!attcan!uunet!intercon!news
From: amanda@mermaid.intercon.com (Amanda Walker)
Newsgroups: comp.sys.mac.programmer
Subject: Re: MPW C++ - MI and HandleObject
Message-ID: <1990Apr13.161623.17288@intercon.com>
Date: 13 Apr 90 16:16:23 GMT
References: <255@unf7.UUCP>
Sender: usenet@intercon.com (USENET The Magnificent)
Reply-To: amanda@mermaid.intercon.com (Amanda Walker)
Organization: InterCon Systems Corporation, Herndon, VA
Lines: 14

In article <255@unf7.UUCP>, shite@unf7.UUCP (Stephen Hite) writes:
> The Apple C++ reference says that multiple inheritance cannot be
> used in combination with HandleObject. 

It's an artifact of the way multiple inheritance is implemented in C++.
In simple terms, pointers are indistinguishable, so you can take a pointer
to a block of instance variables and pretend it's an object in its own
right.  You can't make a Handle that refers to a piece of another Handle...

--
Amanda Walker, InterCon Systems Corporation
--
"Y'know, you can't have, like, a light, without a dark to stick it in...
 You know what I'm sayin'?"     --Arlo Guthrie