[SystemSafety] A small taste of what we're up against

[paul cleary]

I'd like to see an ALARP argument for software written in C. Does anyone
have one to share?

Oh dear, ALaRP arguments can’t just be copied and pasted, it requires context and thought, I suggest writing one yourself.

How would you render that argument, in free text or a GSN pattern?

Kind Regards
Paul Cleary

Sent from my iPhone

On 25 Oct BE 2561, at 10:59, Andrew Banks <andrew at andrewbanks.com<mailto:andrew at andrewbanks.com>> wrote:

I'd like to see an ALARP argument for software written in C. Does anyone
have one to share?

Well... this is where works such as MISRA, CERT et al *help* as they seek to
eliminate some of the stupidities that the language allows.

And yet when some of us call for the ISO C Working Group to fix the
Standard, there are howls of outrage, and claims that there is nothing wrong
with it :(

A couple of years ago, I was at a conference at the Royal Society, where two
*separate* (academic, well-funded) groups presented their work on formal
proving of JavaScript... I suggested one should have done C instead...

A


-----Original Message-----
From: systemsafety
[mailto:systemsafety-bounces at lists.techfak.uni-bielefeld.de] On Behalf Of
Martyn Thomas
Sent: 24 October 2018 10:26
To: systemsafety at lists.techfak.uni-bielefeld.de<mailto:systemsafety at lists.techfak.uni-bielefeld.de>
Subject: Re: [SystemSafety] A small taste of what we're up against

"Support destructive testing of software ! " ??   I'd say "Support
programming languages with unambiguous semantics. "

I'd like to see an ALARP argument for software written in C. Does anyone
have one to share?

Martyn


On 24/10/2018 08:13, Olwen Morgan wrote:

Just a quickie:

if, in the code below, you replace:


    PrintEvalOrder((a[0]=++i), (a[1]=++i), (a[2]=++i));

with:


    PrintEvalOrder((++i), (++i), (++i));

both clang and tcc tell you the order of evaluation is p1, p2, p3
whereas gcc says it's p3, p3, p3. ... WTF?

Presumably, this is due to over-zealous optimisation,


Support destructive testing of software !



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