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From: phils@chaos.cs.brandeis.edu (Phil Shapiro)
Newsgroups: comp.sys.mac.programmer
Subject: Re: "bus error" on GetPort
Message-ID: <PHILS.90Nov6101051@chaos.cs.brandeis.edu>
Date: 6 Nov 90 15:10:51 GMT
References: <85692@tut.cis.ohio-state.edu>
Sender: @chaos.cs.brandeis.edu
Distribution: usa
Organization: Symantec Corp.
Lines: 36
In-Reply-To: brown-t@carp.cis.ohio-state.edu's message of 6 Nov 90 00:43:07 GMT

In article <85692@tut.cis.ohio-state.edu> brown-t@carp.cis.ohio-state.edu (ted croft brown) writes:
   I have come across a probelem that has me REALLY confused.  I am programming
   in THINK C 4.02.  I am in the process of writting my first Macintosh C
   program (and it's been *educational*).

   Anyway, in writting  Modal dialogs I do...

   HandleMenuCommand()
   {
	   WindowPtr window

   .
   .
	   GetPort(window);
	   DoDialogRoutine();
	   SetPort(window);
   }

What you really want to do here is:

    GetPort(&window);

Since GetPort() expects a VAR parameter, you must pass the WindowPtr
by address.  The reason it worked on some computers is because you
were storing your WindowPtr to a random place in memory that happened
to be even and (apparently) unused.

You might want to check out "MacProto.h" header file, it contains
prototypes for most Mac Toolbox calls, and would catch mistakes like
the above.  It's available from most ftp sites.

	-phil
--
   Phil Shapiro                           Technical Support Analyst
   Language Products Group                     Symantec Corporation
		Internet: phils@chaos.cs.brandeis.edu