Path: utzoo!attcan!uunet!cs.utexas.edu!tut.cis.ohio-state.edu!ucbvax!hoptoad!tim
From: tim@hoptoad.uucp (Tim Maroney)
Newsgroups: comp.sys.mac.programmer
Subject: Re: HELP! ID=01 on a Mac II
Message-ID: <9073@hoptoad.uucp>
Date: 24 Nov 89 20:16:32 GMT
References: <1989Nov24.035604.27499@agate.berkeley.edu>
Reply-To: tim@hoptoad.UUCP (Tim Maroney)
Organization: Eclectic Software, San Francisco
Lines: 47

In article <1989Nov24.035604.27499@agate.berkeley.edu>
silverio@brahms.berkeley.edu (C J Silverio) writes:
>I wrote a nifty program on my Plus. Used Think C v4, ANSI library,
>very little Macish stuff at all. Runs just great.  Never crashes. Runs
>fine under Multifinder/6.0.4. Takes up maybe 60K of memory. Didn't try
>heap scrambling yet.
>
>So I pop it on a Mac II and get an ID=01 in the same spot every time.
>8 Megs, turned off all the inits, 6.0.3, turned off Multifinder, bomb
>bomb bomb same spot. Right while plonking a PICT into a window during
>the program start. The mac is all warmed up at this point -- all calls
>to InitThis and InitThat are made.
>
>My pal says "dollars to doughnuts it's an alignment problem." OK,
>cool, pretty easy to fix, right?

Dollars to doughnuts it isn't.  The Plus uses a 68000, which is very
nervous about alignment.  The Mac II uses a 68020, which is much more
relaxed.  The 68020 can cope with pointers on pretty much any alignment,
though I understand there's a bit of extra overhead for using unaligned
pointers (something about an internal exception handler having to fire).
If it ran on the Mac II but not on the Plus, then it would probably
be an alignment problem, but not the other way around.

Try heap scramble.  That may bring it to the top if it's an unlocked
handle problem.  That would be my best bet.  Are you perhaps doing
something like (*x)->y = NewHandle(z), with x unlocked?  I have seen
things like this consistently succeed on one model and fail on another
due to the different memory configurations.

>Natch, I don't have a MacII hanging around to debug on -- I'll just
>have to borry one.

Try heap scramble on your Plus first.

Oh, one more thing.  You didn't mention whether the Mac II was a color
machine. Since this happens during graphics, if the machine is color,
it would change my best bet to that.  Some fields of a grafport are
not the same on a color system.
-- 
Tim Maroney, Mac Software Consultant, sun!hoptoad!tim, tim@toad.com

FROM THE FOOL FILE:
"The negro slaves of the South are the happiest, and, in some sense, the
 freest people in the world.  The children and the aged and infirm work not
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