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From: dewar@merv.cs.nyu.edu (Robert Dewar)
Subject: Re: Renaming Fixed Point Mutiplicative operator in Ada 95
Date: 1998/05/21
Message-ID: <dewar.895785693@merv>#1/1
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Date: 1998-05-21T00:00:00+00:00
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<<Multiplication was just an example of the compilation problem  - division
is the REAL killer - how do you cope with divide-by-zero exceptions in
critical system when all you are allowed is the catch-all exception
handler, (and run-time checks switched off)? Terminating with an exception
is not an option when you are 2 miles above the Atlantic!  I would prefer
to know EXACTLY what is going on in as much of the object code produced
than leave it to the whim of the compiler.
>>


Incidentally, in a critical system, I would jolly well hope that EITHER

 a) you prove that division by zero cannot happen

or

 b) you test for it explicitly

    if z = 0 then
	....
    else
        a := y /z;
    end if;

Once again, I think this is way overblown. Incidentally, I find that having
the convention be that the compiler generates run time checks but you do
NOT permit exception handlers to be a diabolical one. Sounds like another
Ariane on the way. WHo on earth came up with that brilliant designed-to-
cause-trouble decision!

It is that decision that is causing you heartburn, and not surprisingly
so, rather than anything to do with redefining division!