Re: bart again (UCX64)

From	Kaz Kylheku <864-117-4973@kylheku.com>
Newsgroups	comp.lang.c
Subject	Re: bart again (UCX64)
Date	2023-09-07 15:52 +0000
Organization	A noiseless patient Spider
Message-ID	<20230907082050.403@kylheku.com> (permalink)
References	(19 earlier) <b9e00c9c-e879-49d2-a00a-05256b87d766n@googlegroups.com> <87v8coqcpa.fsf@bsb.me.uk> <86zg1ymvvv.fsf@linuxsc.com> <20230906223634.465@kylheku.com> <3b850d75-ae05-4c31-a3d6-9b0333de84abn@googlegroups.com>

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On 2023-09-07, Malcolm McLean <malcolm.arthur.mclean@gmail.com> wrote:
> On Thursday, 7 September 2023 at 07:10:49 UTC+1, Kaz Kylheku wrote:
>> 
>> I'm quite puzzled by your angle which seems to be that if the 
>> reachability diagnostic cannot be done accurately, due to theory, 
>> translation units and run-time conditions/inputs, then it's 
>> a bad diagnostic not worth doing (or at least not worth having 
>> right in the language). Pardon me if I'm misconstruing antyhing. 
>> 
> Take this one.
>
> int gamemainloop(void)
> {
>     if (allocatememorybuffers() == -1)
>        return -1;  // out of memory;
>    if (hardwaretest() == FAIL)
>         return -2; // proper hardware not installed
>     loopforever();  // update / render loop, never returns
> }
>
> Obviously to prove that loopforever loops forever we need to examine it.

Unless there is a good reason for the int return type, it should be
changed to void.

If it doesn't return, it deosn't return int; it returns nothing.

> And even if we could, its the halting problem - most real programs written
> by humans can be trivially proven to either halt or run forever, but it's hard
> to write that requirement into a programming language.

It's not merely hard; it's unwise to even contemplate. Equally unwise
to be deterred from making useful requirements.

>> Do you have in mind examples of situations in which false positives 
>> would cause problems, or even just irk the programmer? 
>>
> We could put a return 0 at the bottom of the fucntion, but that would falsely
> imply that in some circumstances it returns 0. 

That goes hand-in-hand with its declaration, which falsely implies that
the function returns int, do do which it has to return.

If we believe that loopforever() doesn't return, and we cannot change
the return type for whatever reason, we could put an abort() call at the
end of the function.

-- 
TXR Programming Language: http://nongnu.org/txr
Cygnal: Cygwin Native Application Library: http://kylheku.com/cygnal
Mastodon: @Kazinator@mstdn.ca
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Re: bart again (UCX64) David Brown <david.brown@hesbynett.no> - 2023-09-04 10:54 +0200
  Re: bart again (UCX64) Bart <bc@freeuk.com> - 2023-09-04 11:06 +0100
    Re: bart again (UCX64) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-09-04 14:54 +0100
      Re: bart again (UCX64) Bart <bc@freeuk.com> - 2023-09-04 22:02 +0100
        Re: bart again (UCX64) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-09-05 01:31 +0100
          Re: bart again (UCX64) Bart <bc@freeuk.com> - 2023-09-05 02:24 +0100
            Re: bart again (UCX64) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-09-06 04:29 +0100
              Re: bart again (UCX64) Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-09-05 21:06 -0700
              Re: bart again (UCX64) Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2023-09-06 01:03 -0700
                Re: bart again (UCX64) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-09-06 20:58 +0100
                Re: bart again (UCX64) Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2023-09-06 19:21 -0700
                Re: bart again (UCX64) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-09-07 20:18 +0100
              Re: bart again (UCX64) Bart <bc@freeuk.com> - 2023-09-06 13:07 +0100
                Re: bart again (UCX64) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-09-06 22:41 +0100
                Re: bart again (UCX64) Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-09-06 15:56 -0700
                Re: bart again (UCX64) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-09-07 00:53 +0100
                Re: bart again (UCX64) Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-09-06 18:47 -0700
                Re: bart again (UCX64) Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-09-06 17:25 -0700
          Re: bart again (UCX64) Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2023-09-04 18:30 -0700
            Re: bart again (UCX64) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-09-06 03:04 +0100
              Re: bart again (UCX64) Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-09-06 21:48 -0700
                Re: bart again (UCX64) Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-07 06:10 +0000
                Re: bart again (UCX64) Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2023-09-07 02:06 -0700
                Re: bart again (UCX64) Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-07 15:52 +0000
                Re: bart again (UCX64) Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-09-07 14:18 -0700
                Re: bart again (UCX64) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-09-07 15:28 +0100
                Re: bart again (UCX64) David Brown <david.brown@hesbynett.no> - 2023-09-07 16:54 +0200
                Re: bart again (UCX64) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-09-07 17:02 +0100
                Re: bart again (UCX64) Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-07 16:12 +0000
                Re: bart again (UCX64) scott@slp53.sl.home (Scott Lurndal) - 2023-09-07 16:17 +0000
                Re: bart again (UCX64) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-09-07 17:37 +0100
                Re: bart again (UCX64) Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-09-07 14:51 -0700
                Re: bart again (UCX64) Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2023-09-08 00:46 -0700
                Re: bart again (UCX64) David Brown <david.brown@hesbynett.no> - 2023-09-08 11:06 +0200
                Re: bart again (UCX64) David Brown <david.brown@hesbynett.no> - 2023-09-08 10:19 +0200
                Re: bart again (UCX64) Bart <bc@freeuk.com> - 2023-09-07 15:55 +0100
                Re: bart again (UCX64) scott@slp53.sl.home (Scott Lurndal) - 2023-09-07 15:16 +0000
                Re: bart again (UCX64) Bart <bc@freeuk.com> - 2023-09-07 17:02 +0100
                Re: bart again (UCX64) scott@slp53.sl.home (Scott Lurndal) - 2023-09-07 16:15 +0000
                Re: bart again (UCX64) Bart <bc@freeuk.com> - 2023-09-07 17:51 +0100
                Re: bart again (UCX64) scott@slp53.sl.home (Scott Lurndal) - 2023-09-07 17:24 +0000
                Re: bart again (UCX64) Bart <bc@freeuk.com> - 2023-09-07 21:53 +0100
                Re: bart again (UCX64) scott@slp53.sl.home (Scott Lurndal) - 2023-09-07 21:34 +0000
                Re: bart again (UCX64) scott@slp53.sl.home (Scott Lurndal) - 2023-09-07 17:25 +0000
                Re: bart again (UCX64) Bart <bc@freeuk.com> - 2023-09-07 21:37 +0100
                Re: bart again (UCX64) scott@slp53.sl.home (Scott Lurndal) - 2023-09-07 21:02 +0000
                Re: bart again (UCX64) Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-09-07 16:14 -0700
                Re: bart again (UCX64) Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-09-07 16:09 -0700
                Re: bart again (UCX64) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-09-07 17:34 +0100
                Re: bart again (UCX64) scott@slp53.sl.home (Scott Lurndal) - 2023-09-07 17:22 +0000
                Re: bart again (UCX64) Richard Damon <Richard@Damon-Family.org> - 2023-09-07 11:44 -0700
                Re: bart again (UCX64) Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-09-07 15:16 -0700
                Re: bart again (UCX64) Bart <bc@freeuk.com> - 2023-09-07 23:48 +0100
                Re: bart again (UCX64) Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-09-07 17:16 -0700
                Re: bart again (UCX64) David Brown <david.brown@hesbynett.no> - 2023-09-08 11:16 +0200
                Re: bart again (UCX64) Bart <bc@freeuk.com> - 2023-09-08 10:51 +0100
                Re: bart again (UCX64) David Brown <david.brown@hesbynett.no> - 2023-09-08 13:00 +0200
                Re: bart again (UCX64) Bart <bc@freeuk.com> - 2023-09-08 13:05 +0100
                Re: bart again (UCX64) David Brown <david.brown@hesbynett.no> - 2023-09-08 16:11 +0200
                Re: bart again (UCX64) Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-09 00:56 +0000
                Re: bart again (UCX64) Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-09 00:47 +0000
                Re: bart again (UCX64) David Brown <david.brown@hesbynett.no> - 2023-09-09 18:49 +0200
                Re: bart again (UCX64) Richard Damon <Richard@Damon-Family.org> - 2023-09-09 10:27 -0700
                Re: bart again (UCX64) David Brown <david.brown@hesbynett.no> - 2023-09-10 12:06 +0200
                Re: bart again (UCX64) Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-09-08 05:03 -0700
                Re: bart again (UCX64) Bart <bc@freeuk.com> - 2023-09-08 13:39 +0100
                Re: bart again (UCX64) candycanearter07 <no@thanks.net> - 2023-09-08 07:49 -0500
                Re: bart again (UCX64) Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-09 01:07 +0000
                Re: bart again (UCX64) David Brown <david.brown@hesbynett.no> - 2023-09-09 18:51 +0200
                Re: bart again (UCX64) David Brown <david.brown@hesbynett.no> - 2023-09-08 16:35 +0200
                Re: bart again (UCX64) Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-09 01:04 +0000
    Re: bart again (UCX64) scott@slp53.sl.home (Scott Lurndal) - 2023-09-04 14:14 +0000
    Re: bart again (UCX64) David Brown <david.brown@hesbynett.no> - 2023-09-04 16:59 +0200
      Re: bart again (UCX64) Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-09-04 15:41 -0700
        Re: bart again (UCX64) Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-09-04 18:15 -0700
          Re: bart again (UCX64) Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-09-04 18:57 -0700

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