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From: lsr@Apple.com (Larry Rosenstein)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Simple questions regarding MultiFinder and File Referencing
Message-ID: <11783@goofy.Apple.COM>
Date: 19 Jan 91 01:39:53 GMT
References: <91048.134609BRBOYER@MTUS5.BITNET> <1991Jan17.220745.1621@engin.umich.edu>
Sender: usenet@Apple.COM
Organization: Apple Computer, Inc.
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In article <1991Jan17.220745.1621@engin.umich.edu>, mystone@mondo.engin.umich.edu (Dean Yu) writes:
> 
>   When your application is first launched, the directory containing your
> application (or the directory containing the documents you launched with) is
> set to the default directory.  You can get the working directory reference
> number with a call to _GetVol.

You should call GetVol at the very start of your program and save the
result away.  The reason is that some versions of TOPS (2.x at least) 
will change the current volume on you if a floppy disk is inserted.  I
think that TOPS call PBHGetVol/PBHSetVol internally, which is a no-no
according to Tech Note #140.

Alternatively, you can use PBHGetVol and use the dirID that it returns in
PBHOpen, for example.