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From: lsr@Apple.COM (Larry Rosenstein)
Newsgroups: comp.sys.mac.programmer
Subject: Re: How can I know if an application is already running?
Message-ID: <5839@internal.Apple.COM>
Date: 18 Dec 89 21:54:23 GMT
Sender: usenet@Apple.COM
Organization: Objects-R-Us,  Apple Computer, Inc.
Lines: 22
References:<8581@cs.yale.edu> <1042@maytag.waterloo.edu>

In article <1042@maytag.waterloo.edu> jb@aries5.uucp (James Bruyn) writes:
> by Apple, and won't work if somebody changes the application name - walk
> through the FCB's looking for the file name.  Or if you really want to
> be picky, check creator and file type of every open file.

It is probably better to call PBGetFInfo and check the value of ioFRefnum. 
 Inside Mac volume 4 (p. 149) says this will be the reference number of 
the first access path found.  If it's non-zero then the file is open.  
(Although I think on 64K ROMs, the system doesn't clear this if the file 
isn't open, so you should clear this field before making the call.)

Also, the same call returns a set of flags in ioFlAttrib which indicate 
whether the resource and/or data fork is open (IM volume 4 p. 122).

In ApplicationMenu is check for ioRefnum <> 0 to tell whether the DA 
Handler file is open, and therefore whether there is a DA layer.

Larry Rosenstein, Apple Computer, Inc.
Object Specialist

Internet: lsr@Apple.com   UUCP: {nsc, sun}!apple!lsr
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