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From: clubmac@runx.UUCP
Newsgroups: comp.sys.mac
Subject: Re: Getting a vRefNum from a DirID
Message-ID: <1180@runx.ips.oz>
Date: Wed, 28-Oct-87 23:51:08 EST
Article-I.D.: runx.1180
Posted: Wed Oct 28 23:51:08 1987
Date-Received: Sun, 1-Nov-87 07:43:21 EST
References: <1006@mntgfx.MENTOR.COM>
Reply-To: clubmac@runx.OZ (Macintosh Users Group - Sydney, Australia)
Organization: RUNX  Un*x Timeshare. Sydney, Australia.
Lines: 64

In article <1006@mntgfx.MENTOR.COM> tomc@mntgfx.MENTOR.COM (Tom Carstensen) writes:
>Put simply, how do you get a volume reference number
>(like that return from a SFGetFile), from a directory
>ID?  
>
>I've tried about everything!  help!

Since I asked the same question a couple of months back and with the help of
John O'Neill and Andrew Betzis, here is some LSC code to do the job.

Jason Haines, President

Club Mac Macintosh Users Group, Sydney, Australia
Phone Home: +61-02-73-4444
Snail:      Box 213, Holme Building, Sydney University, NSW, 2006, Australia
ACSnet:     clubmac@runx.ips.oz	   ARPA:   clubmac%runx.ips.oz@seismo.css.gov
UUCP:{enea,hplabs,mcvax,prlb2,seismo,ubc-vision,ukc}!munnari!runx.ips.oz!clubmac

---
#include <HFS.h>
#include <stdio.h>

/* Given a working directory refnum, return the volume refnum and dirID.
	This assumes that HFS is installed on the machine.  */

OSErr GetDirID(vRefNum,dirID)
int		*vRefNum;
long	*dirID;
{
	WDPBRec	pb;
	long	result;
	
	pb.ioCompletion = NULL;
	pb.ioNamePtr = NULL;
	pb.ioVRefNum = *vRefNum;
	pb.ioWDIndex = 0;
	pb.ioWDProcID = 0;
	pb.ioWDVRefNum = *vRefNum;
	result = PBGetWDInfo(&pb, FALSE);
	*vRefNum = pb.ioWDVRefNum;
	*dirID = pb.ioWDDirID;
	return(result);
}

/* This is the reverse */

OSErr DirID2VRefNum(VRefNum,dirID)
int		*VRefNum
long	*dirID
{
	WDPBRec		theWD;
	OSErr		err;

	theWD.ioCompletion = NULL;
	theWD.ioNamePtr = NULL;
	theWD.ioVRefNum = 0;
	theWD.ioWDDirID = *dirID;
	theWD.ioWDProcID = 'ERIK';
	err = PBOpenWD(&theWD,FALSE);
	*VRefNum = theWD.ioVRefNum;
	return(err);
}
---
Hope this helps.