Article View: comp.windows.ms.programmer
Article #367Re: Goodbye UAE?
From: Milan Shah
Date: Tue, 14 Apr 1992 19:13
Date: Tue, 14 Apr 1992 19:13
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Or can we? Just because the message is gone, doesn't mean that a new
UAE dialog isn't out there, waiting.
I can't believe how badly misunderstood this 'No UAE' business has. Pray,
tell me, as a programmer, how in hey do you expect *any* OS to detect
and correct an error in an application? What do you want Windows to do
when you dereference a Null pointer?
UAE's were terrible because of the following - an application error would
not be detected at the time of the error, but would manifest itself later
on at seemingly completely random times. So for example, Program A could
do something illegal (like delete a resource not belonging to it), things
would continue fine, and then later on, Program B, owner of resource,
dies with UAE. Now, the poor programmer of Program B is trying to figure
out what s/he did wrong. (This is probably a bad example, but you get the
point)
The GPF flags an error when it occurs, so that the fault is correctly
identified to be with Program A.
The following program will die under every OS of the past, present, and
future: whether you call it UAE, GPF, segmentation fault, bus error, or
whatever.
void main()
{
int *pnCrash;
pnCrash = 0;
*pnCrash = 1;
}
The big improvement in Windows is not that UAE's don't occur (they *must*,
if there is an error in the user program), but that they are *detected*
correctly and at the time the error occurs.
Milan
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Newsgroups: comp.windows.ms.programmer Path: arc1-ca.pugleaf.net!sparky!uunet!snorkelwacker.mit.edu!bloom-picayune.mit.edu!news.mit.edu!mmshah From: mmshah@im.lcs.mit.edu (Milan Shah) Subject: Re: Goodbye UAE? In-Reply-To: slo@otter.hpl.hp.com's message of Tue, 14 Apr 1992 09:37:54 GMT Message-ID: <MMSHAH.92Apr14141355@im5.lcs.mit.edu> Sender: news@athena.mit.edu (News system) Nntp-Posting-Host: im5.lcs.mit.edu Organization: MIT Lab for Computer Science References: <72170034@otter.hpl.hp.com> Date: Tue, 14 Apr 1992 19:13:55 GMT Lines: 41