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From: toddpw@nntp-server.caltech.edu (Todd P. Whitesel)
Newsgroups: comp.sys.apple2
Subject: Re: Multiswitch GS!
Message-ID: <1991Apr2.070426.23818@nntp-server.caltech.edu>
Date: 2 Apr 91 07:04:26 GMT
References: <156810@tiger.oxy.edu> <13207@ucrmath.ucr.edu>
Organization: California Institute of Technology, Pasadena
Lines: 23

rhyde@gibson.ucr.edu (randy hyde) writes:

>Have they solved the problem with the GS/OS close all command?
>About three years ago I looked at this problem.  Even had a multi-ANIX
>up and running.  Alas, the GS/OS close call (with sub-code zero, as I
>recall) closed all open files.  If one program executed this command, it
>closed *all* open files, including those opened by other applications.
>I gave up at the time because I was not willing to write a complex front-end
>for GS/OS to capture this call.

I can't answer for the french guys, but I have thought about this one. All
you need to do is apply the UserID matching criteria that the Memory Manager
uses for DisposeAll() calls. Close calls with refnum's of 0 are extremely
rare anyways, because of the lack of UserID protection.

The UserID system and certain hooks in the system designed solely for
MultiFinder-type switching have existed since day 1; The last barrier to
a real switcher is GS/OS itself. It is rumored that the next version of GS/OS
will allow proper context switching and so on, in order to make cooperative
multitasking possible.

Todd Whitesel
toddpw @ tybalt.caltech.edu