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From: "Chad R. Meiners" <crmeiners@hotmail.com>
Newsgroups: comp.arch.embedded,comp.lang.ada
Subject: Re: Certified C compilers for safety-critical embedded systems
Date: Sun, 28 Dec 2003 17:59:06 -0500
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"Chris Hills" <chris@phaedsys.org> wrote in message
news:GawT1aBurv7$EA8G@phaedsys.demon.co.uk...
> In article <bsmagl$e5ajv$1@ID-69815.news.uni-berlin.de>, Peter Amey
> <peter.amey@praxis-cs.co.uk> writes
> >(for example,
> >why deep static analysis of _any_ general-purpose langauge is
> >impossible;
>
> Interesting.... can you explain? Perhaps as a separate thread?

Rice's theorem states this.  It is a result of the undecidablility of the
Halting problem, and it is also related to Godel's incompleteness theorem.
I would suggest taking a class on computation theory, but it might suffice
to read a book on computation theory and work through the problems.

> >or, why systems of integrities in the better-than 10e-6
> >failures per hour class _require_ deep static analysis);
>
> Is that a contradiction or do you mean that you need static analysis but
> it can never be 100%?

No it isn't a contradiction.  SPARK is not a general purpose language; it is
a special purpose language (SPARK is not Turing-Complete hence Rice's
theorem doesn't apply to it), which is designed to facilitate deep static
analysis.