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From: lsr@apple.UUCP (Larry Rosenstein)
Newsgroups: comp.sys.mac
Subject: Re: HFS Query (Why PBHSetVol is Dangerous)
Message-ID: <1355@apple.UUCP>
Date: Thu, 23-Jul-87 13:00:56 EDT
Article-I.D.: apple.1355
Posted: Thu Jul 23 13:00:56 1987
Date-Received: Sat, 25-Jul-87 08:45:04 EDT
References: <1020@runx.ips.oz> <2496@hoptoad.uucp>
Reply-To: lsr@apple.UUCP (Larry Rosenstein)
Organization: Advanced Technology Group, Apple Computer
Lines: 28

In article <2496@hoptoad.uucp> tim@hoptoad.UUCP (Tim Maroney) writes:
>
>The working directory calls crash the system on MFS systems, and are among
>the most headachey routines of HFS anyway.  Instead, you should simply use
>the HFS call PBHSetVol, which works fine on MFS systems and doesn't
>require diddling around with working directories.

The working directory calls are not implemented on MFS systems.  On MFS
disks, there is no problem because there are no folders.  I agree that it
is inconvenient to create a working directory, but it is not very
difficult to test whether HFS is installed.

Tech Note 140 (just released) cautions agains using PBHSetVol.  The reason
is that if you pass a dirID to PBHSetVol, the File Manager stores it
separately from the volume refnum.  If you (or some DA) then call GetVol
(or PBGetVol) all you will get back is the volume refnum.  This is
particularly bad for DAs, since they cannot know that you have called
PBHSetVol. 

-- 
Larry Rosenstein

Object Specialist
Apple Computer

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