Re: arm-gcc: pointer to constant string

From	David Brown <david.brown@hesbynett.no>
Newsgroups	comp.arch.embedded
Subject	Re: arm-gcc: pointer to constant string
Date	2018-09-18 08:49 +0200
Organization	A noiseless patient Spider
Message-ID	<pnq76n$kos$1@dont-email.me> (permalink)
References	(11 earlier) <3ranD.175206$_V.125892@fx32.am4> <pnlk5e$ntf$1@dont-email.me> <7ZsnD.408545$%L2.113927@fx15.am4> <pnmd4r$3h8$1@dont-email.me> <pnpn9t$i6j$1@dont-email.me>

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On 18/09/18 04:24, Les Cargill wrote:
> David Brown wrote:
>> On 16/09/18 15:33, Tom Gardner wrote:
>>> On 16/09/18 14:00, David Brown wrote:
> <snip>
>>
>> There are few cases where formal proofs are worth the time and costs
>> involved.  But I like - when possible - to write my code with a view
>> that a formal proof /could/ be made if someone were to go to the
>> effort.   It is rare that you could prove a whole program - but not
>> uncommon that you could (if you wanted to) prove many of the functions
>> involved. Thinking in terms of pre-conditions, invariants,
>> post-conditions, variants, specifications - that is all good stuff for
>> writing solid code, even if you don't do so formally.
>>
> 
> If you stick to something akin to the Haskell Actor model and everything
> is an event, it's not too onerous to use combinators to generate a
> significant subset of all messages. With the proper level of
> introspection, you can "prove" the program works to a limit
> enumerated by the test vectors and that it continues to do so as
> changes are made to the code base.
> 

Testing can /never/ prove a program is correct - unless you can
enumerate /all/ inputs and states of your code and go through them all.
 Testing can prove a program is wrong (and it is vital for that), but it
cannot prove a program is correct.

A functional programming language like Haskell gives you a much better
chance of actually proving the correctness of your code than an
imperative language like C - that is one of the reasons for the
existence of functional programming languages (it is the lack of state
and side-effects that help).  But if you want to prove the correctness
of your Haskell program, you do it by an analysis of the code, or by
deriving correct code in the first place - you don't do it by testing.

> The test vectors and captured output can be controlled and
> compared to. And if you want to go as far as model
> checking or partial model checking, you have the stuff in place to
> enforce that now.
> 
> 
> Obviously, there are domains where you just can't get close enough to
> this ideal. So you gamble.
> 

Indeed - and almost all practical situations fall into this category.

> <snip>
> 
>>
>> Certainly I do not think C is the best choice of language for many of
>> the types of use it is put to.  I think most people who program in C
>> would be more productive and write more correct code in other
>> languages - and most programs that are written in C would be better
>> written in other languages.
>>
> 
> Possibly. But what C offers is the ability to build nonstandard, hybrid
> "furniture" to support the development effort that can not be
> forseen by language and library designers. This is especially pronounced
> in serialization and the ability to dynamically configure a program  (
> which are two sides of the same coin ).
> 

I don't follow that at all.

> C also supports event-driven-ness in a way that few other languages do.
> 

And I follow that even less.

(I am not saying I disagree with you, I just can't see what you are
trying to say.  Maybe I'll understand it better after some coffee.)

C certainly has its important features and strengths, and is a very
useful language to have.

Thread

arm-gcc: pointer to constant string pozz <pozzugno@gmail.com> - 2018-09-14 09:50 +0200
  Re: arm-gcc: pointer to constant string David Brown <david.brown@hesbynett.no> - 2018-09-14 11:18 +0200
    Re: arm-gcc: pointer to constant string pozz <pozzugno@gmail.com> - 2018-09-14 13:05 +0200
      Re: arm-gcc: pointer to constant string David Brown <david.brown@hesbynett.no> - 2018-09-14 13:25 +0200
  Re: arm-gcc: pointer to constant string Nils M Holm <nmh@ananda.local> - 2018-09-14 09:47 +0000
    Re: arm-gcc: pointer to constant string David Brown <david.brown@hesbynett.no> - 2018-09-14 12:26 +0200
      Re: arm-gcc: pointer to constant string Stef <stef33d@yahooI-N-V-A-L-I-D.com.invalid> - 2018-09-14 14:52 +0200
        Re: arm-gcc: pointer to constant string David Brown <david.brown@hesbynett.no> - 2018-09-14 16:04 +0200
          Re: arm-gcc: pointer to constant string Tom Gardner <spamjunk@blueyonder.co.uk> - 2018-09-14 15:48 +0100
            Re: arm-gcc: pointer to constant string David Brown <david.brown@hesbynett.no> - 2018-09-14 17:02 +0200
              Re: arm-gcc: pointer to constant string Tom Gardner <spamjunk@blueyonder.co.uk> - 2018-09-14 18:45 +0100
                Re: arm-gcc: pointer to constant string David Brown <david.brown@hesbynett.no> - 2018-09-14 20:37 +0200
                Re: arm-gcc: pointer to constant string Tom Gardner <spamjunk@blueyonder.co.uk> - 2018-09-14 20:51 +0100
                Re: arm-gcc: pointer to constant string David Brown <david.brown@hesbynett.no> - 2018-09-15 16:24 +0200
                Re: arm-gcc: pointer to constant string Tom Gardner <spamjunk@blueyonder.co.uk> - 2018-09-15 17:28 +0100
                Re: arm-gcc: pointer to constant string Clifford Heath <no.spam@please.net> - 2018-09-16 13:58 +1000
                Re: arm-gcc: pointer to constant string Tom Gardner <spamjunk@blueyonder.co.uk> - 2018-09-16 08:42 +0100
                Re: arm-gcc: pointer to constant string Tom Gardner <spamjunk@blueyonder.co.uk> - 2018-09-16 08:47 +0100
                Re: arm-gcc: pointer to constant string Clifford Heath <no.spam@please.net> - 2018-09-16 20:18 +1000
                Re: arm-gcc: pointer to constant string Tom Gardner <spamjunk@blueyonder.co.uk> - 2018-09-16 12:25 +0100
                Re: arm-gcc: pointer to constant string Clifford Heath <no.spam@please.net> - 2018-09-16 22:22 +1000
                Re: arm-gcc: pointer to constant string David Brown <david.brown@hesbynett.no> - 2018-09-16 15:00 +0200
                Re: arm-gcc: pointer to constant string Tom Gardner <spamjunk@blueyonder.co.uk> - 2018-09-16 14:33 +0100
                Re: arm-gcc: pointer to constant string David Brown <david.brown@hesbynett.no> - 2018-09-16 22:06 +0200
                Re: arm-gcc: pointer to constant string Tom Gardner <spamjunk@blueyonder.co.uk> - 2018-09-16 21:42 +0100
                Re: arm-gcc: pointer to constant string Les Cargill <lcargill99@comcast.com> - 2018-09-17 21:24 -0500
                Re: arm-gcc: pointer to constant string David Brown <david.brown@hesbynett.no> - 2018-09-18 08:49 +0200
                Re: arm-gcc: pointer to constant string Les Cargill <lcargill99@comcast.com> - 2018-09-21 22:15 -0500
                Re: arm-gcc: pointer to constant string David Brown <david.brown@hesbynett.no> - 2018-09-22 11:53 +0200
                Testing (Was: arm-gcc: pointer to constant string) Jacob Sparre Andersen <jacob@jacob-sparre.dk> - 2018-09-22 12:16 +0200
                Re: Testing (Was: arm-gcc: pointer to constant string) David Brown <david.brown@hesbynett.no> - 2018-09-22 13:31 +0200
                Re: Testing (Was: arm-gcc: pointer to constant string) Clifford Heath <no.spam@please.net> - 2018-09-23 09:26 +1000
                Re: arm-gcc: pointer to constant string Niklas Holsti <niklas.holsti@tidorum.invalid> - 2018-09-22 20:06 +0300
                Re: arm-gcc: pointer to constant string David Brown <david.brown@hesbynett.no> - 2018-09-23 14:39 +0200
                Re: arm-gcc: pointer to constant string Les Cargill <lcargill99@comcast.com> - 2018-09-22 13:50 -0500
                Re: arm-gcc: pointer to constant string David Brown <david.brown@hesbynett.no> - 2018-09-23 15:21 +0200
                Re: arm-gcc: pointer to constant string Tom Gardner <spamjunk@blueyonder.co.uk> - 2018-09-23 16:06 +0100
                Re: arm-gcc: pointer to constant string julio@diegidio.name - 2018-09-23 08:41 -0700
                Re: arm-gcc: pointer to constant string Tom Gardner <spamjunk@blueyonder.co.uk> - 2018-09-23 16:49 +0100
                Re: arm-gcc: pointer to constant string julio@diegidio.name - 2018-09-23 08:56 -0700
                Re: arm-gcc: pointer to constant string Tom Gardner <spamjunk@blueyonder.co.uk> - 2018-09-23 18:20 +0100
                Re: arm-gcc: pointer to constant string julio@diegidio.name - 2018-09-23 12:05 -0700
                Re: arm-gcc: pointer to constant string Tom Gardner <spamjunk@blueyonder.co.uk> - 2018-09-23 20:50 +0100
                Re: arm-gcc: pointer to constant string Les Cargill <lcargill99@comcast.com> - 2018-09-23 12:04 -0500
                Re: arm-gcc: pointer to constant string Tom Gardner <spamjunk@blueyonder.co.uk> - 2018-09-23 18:27 +0100
                Re: arm-gcc: pointer to constant string David Brown <david.brown@hesbynett.no> - 2018-09-23 19:37 +0200
                Re: arm-gcc: pointer to constant string Jacob Sparre Andersen <jacob@jacob-sparre.dk> - 2018-09-24 12:53 +0200
                Re: arm-gcc: pointer to constant string David Brown <david.brown@hesbynett.no> - 2018-09-24 13:49 +0200
                Re: arm-gcc: pointer to constant string Les Cargill <lcargill99@comcast.com> - 2018-09-28 20:17 -0500
                Re: arm-gcc: pointer to constant string Tom Gardner <spamjunk@blueyonder.co.uk> - 2018-09-18 08:32 +0100
                Re: arm-gcc: pointer to constant string David Brown <david.brown@hesbynett.no> - 2018-09-18 10:02 +0200
                Re: arm-gcc: pointer to constant string Les Cargill <lcargill99@comcast.com> - 2018-09-21 22:17 -0500
          Re: arm-gcc: pointer to constant string Stef <stef33d@yahooI-N-V-A-L-I-D.com.invalid> - 2018-09-14 18:30 +0200
            Re: arm-gcc: pointer to constant string David Brown <david.brown@hesbynett.no> - 2018-09-14 20:46 +0200
      Re: arm-gcc: pointer to constant string Stefan Reuther <stefan.news@arcor.de> - 2018-09-14 19:57 +0200
        Re: arm-gcc: pointer to constant string David Brown <david.brown@hesbynett.no> - 2018-09-14 20:56 +0200
          Re: arm-gcc: pointer to constant string Stefan Reuther <stefan.news@arcor.de> - 2018-09-15 18:32 +0200
            Re: arm-gcc: pointer to constant string David Brown <david.brown@hesbynett.no> - 2018-09-16 15:06 +0200
      Re: arm-gcc: pointer to constant string Richard Damon <Richard@Damon-Family.org> - 2018-09-14 19:59 -0400
        Re: arm-gcc: pointer to constant string David Brown <david.brown@hesbynett.no> - 2018-09-15 16:25 +0200
  Re: arm-gcc: pointer to constant string Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2018-09-14 13:49 +0300

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