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From: pfk@schnecke.offl.uni-jena.de (Frank Klemm)
Subject: Re: Idea: Array Boundary Checks on Write Access Only
Date: 1998/07/09
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References: <35851B64.5BF271C4@cl.cam.ac.uk> <35858FBC.4E5E@praxis-cs.co.uk>
 <dewar.898364494@merv> <358D324F.7848A4A8@cl.cam.ac.uk>
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Organization: Pbzchgre fvaq hasruyone, Qnir
Newsgroups: comp.lang.ada
Date: 1998-07-09T00:00:00+00:00
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On 22 Jun 1998 00:44:07 -0400, Robert Dewar <dewar@merv.cs.nyu.edu> wrote:
>Markus said
>
><<The reason for the crash in the end was an unhandled Ada overflow
>exception. There would have been no problem here if this piece of
>navigation system control code had been compiled without exceptions.
>>>
>
>Indeed, and I often use this case as an example of the important fact that
>runtime checking does not necessarily improve safety, and indeed if exceptions
>can be raised, it is vital that VERY careful analysis of all exceptional
>situations take place to make sure they are handled. In the absence of
>such careful analysis, running with checks on can be much more dangerous
>than with checks off. Very often, a locally violated constraint will just
>cause a local wrong value with checks off, which may not be critical,
>especially if the wrong value is in connection with a non-critical function.
>But raising an exception can have disastrous global effects if the exception
>is not properly handled.
>
Do no check for a condition if you're not known how to handle it!

-- 
Frank Klemm

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