Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!uunet!mcsun!sunic!draken!d88-jwa
From: d88-jwa@nada.kth.se (Jon Watte)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Shutdown Manager
Message-ID: <2794@draken.nada.kth.se>
Date: 22 Jan 90 20:14:07 GMT
References: <1990Jan16.193431.28545@eplrx7.uucp> <1409@smurf.ira.uka.de> <13905@reed.UUCP>
Reply-To: d88-jwa@nada.kth.se (Jon W{tte)
Organization: Royal Institute of Technology, Stockholm, Sweden
Lines: 40

In article <13905@reed.UUCP> chaffee@reed.UUCP (Alex Chaffee) writes:

>I'm not intimately familiar with the Shutdown manager, but I have patched a
>few traps in my time.  I offer the following suggestion:  Patch Shutdown,
>but since you're worried about compatibility, just have that patch set a
>flag somewhere that your real shutdown routine can see it.  Then proceed
>legally and cleanly to _Shutdown...  Presumably, your sdUnmount (or
>sdPowerOff) routine will get called at the right time, look at the flag, and
>if it's been set, put up the dialog box.  Does anyone see a problem with
>this?  Or is it redundant?

Well, the problem was that if your shutdown manager task puts up
the dialog, there's no way to get OUT of the shutdown sequence...

Presumably, though, it's safe to tail-patch _Shutdown, since I
have very grave doubts any buggy core routines will call this,
and thus Apple patch it to fix a bug :-)

Patch _Shutdown
Put up your dialog
If cancel - well, return (with an error ? or ExitToShell() ?)
If not - well, JMP away to the address you got when you patched

Or is there still a better way ?


On the subject of trap patching; I'd like to write an INIT and
FKEY combination that lets me switch keyboard layout without
going into the chooser (or is there one already ?)

I thought about my INIT patching _KeyTrans, and changing the
pointer on the stack to a KCHR I've loaded into memory. Anyone
see a problem with this, except that I'll have to lock the
KCHR down constantly (since _KeyTrans is presumably called at
interrupt time) ?

h+
-- 
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