Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.csd.uwm.edu!bionet!agate!ucbvax!hplabs!well!svc
From: svc@well.UUCP (Leonard Rosenthol)
Newsgroups: comp.sys.mac.programmer
Subject: Re: File Manager question
Summary: Here are the answers!
Keywords: File Manager, prefs, whatever
Message-ID: <13235@well.UUCP>
Date: 20 Aug 89 07:23:54 GMT
References: <15088@dartvax.Dartmouth.EDU>
Reply-To: svc@well.UUCP (Leonard Rosenthol)
Organization: Whole Earth 'Lectronic Link, Sausalito, CA
Lines: 57


>I am fairly new to Mac Programming.  The other day I tackled the
>dreaded IM IV File Manager section because I am writing an application
>that need to save some preference parameters.  There are a number of
>ways that I can think of solving this problem, but I can find a
>solution or a safe solution to this:
>
>1)  Saving the preferences in the data fork of the currently running
>application.
>
	DO NOT DO THIS!  Writing to yourself (either in the datafork or the
resource fork) is not recommended!  Some of reasons for this include the fact
that by doing so, you make you application no longer usuable from a server
under certain conditions...and your users would not be very happy.
>
>2) Saving the preferences in a file in the currently blessed system
>folder.
>
	This is the Apple Approved (and in many ways the easiest) of the ways
to save off preference info.

>Question:  How do I get the vRefNum of the current system Folder ?
>
	Call SysEnvirons (IMV-5).  One of the fields of the sysEnvRec which
is returned to you is the sysVRefNum (ie. the vRefNum of the blessed system
folder).  Quick and painless.
>
>3) Saving the preference in a file in the same folder as the application
>is in.
>
	This will also work, but again this may also have problems on server
volumes depending on the permissions of the apps folder.

>Question:  Similar question as in 1, how can I be sure that the default
>working directory will not be changed ? is passing '0' as vRefNum always
>safe?
>
	What I would do to solve this one is to do a GetVol at the beginning
of the application (right after the rest of the Toolbox inits) and that will
give you the vRefNum of the appls folder for use in writing it out.  This is
also useful when you have owned files such as spelling dictionaries and help
files.

>Much thanks in advance
>
	Anytime!


+--------------------------------------------------+
Leonard Rosenthol        |  GEnie : MACgician
Lazerware, inc.          |  MacNet: MACgician
UUCP: svc@well.UUCP      |  ALink : D0025
-- 
+--------------------------------------------------+
Leonard Rosenthol        |  GEnie : MACgician
Lazerware, inc.          |  MacNet: MACgician
UUCP: svc@well.UUCP      |  ALink : D0025