Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!efi!tim
From: tim@efi.com (Tim Maroney)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Is this file open?
Message-ID: <1990Aug23.154556.13011@efi.com>
Date: 23 Aug 90 15:45:56 GMT
References: <1628@uvm-gen.UUCP>
Organization: Electronics For Imaging, Inc.
Lines: 11

In article <1628@uvm-gen.UUCP> emerson@griffin.uvm.edu (Tree) writes:
>Is there a way to tell if a file returned from SFGetFile is already open?

Yes.  The usual way assumes that all you care about is whether it's
already open in your application; just walk your application's window
list (presumably, you have some internal data structure for your window
list, but if not, you can always walk the system window list starting
at FrontWindow) and see if it's there.  If you want to see if anyone
has it open in any way at all, call PBGetFInfo or PBHGetFInfo on it and
see if the ioRefNum field is positive; if so, it's the refNum that the
file is open under.