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From: earleh@eleazar.dartmouth.edu (Earle R. Horton)
Newsgroups: comp.sys.mac.programmer,comp.sys.mac
Subject: Re: Checking for MF (was Re: Need some MF help)
Message-ID: <12910@dartvax.Dartmouth.EDU>
Date: 5 Apr 89 23:21:17 GMT
References: <1562@neoucom.UUCP> <28689@ucbvax.BERKELEY.EDU> <1179@internal.Apple.COM>
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Reply-To: earleh@eleazar.dartmouth.edu (Earle R. Horton)
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In article <1179@internal.Apple.COM> goldman@apple.com (Phil Goldman) writes:
>In article <28689@ucbvax.BERKELEY.EDU> oster@dewey.soe.berkeley.edu (David 
>Phillip Oster) writes:
>> The standard, from Apple is "Don't even try to do this".  Most people do
>> it by checking to see if the end of the system heap is close to the
>> beginning of the application heap. If it is, no multifinder.
>
>This is a very bad thing to do, and, as was mentioned in a previous 
>posting, the one known legitimate reason for doing so will soon be fixed 
>in SysEnvirons.
>
     I fully agree that it is bad to check for Multifinder in terms of
future compatibility.  If Apple wants developers to refrain from doing
this, they should NOT DISTRIBUTE DEVELOPER'S TOOLS WHICH OBVIOUSLY DO.
I have MPW Shell 2.0.2, and it obviously knows whether Launch will
return or not, and therefore knows whether MultiFinder is active.  It
undoubtedly uses some non-approved method of finding out whether
MultiFinder is active or not.  Apple cannot reasonably expect
developers to refrain from checking for MultiFinder active, and at the
same time sell them a program which does.  "Don't do as I do, do as I
say." is not very convincing coming from anybody.

>
>Doing such checks makes it very much harder to move MultiFinder 
>functionality to the System or ROM.  Worse, it makes it dirtier to add new 
>Mac OS functionality.

     Yes.  I can imagine all sorts of nifty features that could be
added to MultiFinder and the OS, and that would be incompatible with
present applications which check for MultiFinder active.  So please,
don't attempt to find out, and ignore the bad example set by certain
distributors of development systems.

Earle