Re: bart again (UCX64)

From	Keith Thompson <Keith.S.Thompson+u@gmail.com>
Newsgroups	comp.lang.c
Subject	Re: bart again (UCX64)
Date	2023-09-05 13:48 -0700
Organization	None to speak of
Message-ID	<87r0nc4a8y.fsf@nosuchdomain.example.com> (permalink)
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Bart <bc@freeuk.com> writes:
> On 05/09/2023 01:16, Keith Thompson wrote:
>> Bart <bc@freeuk.com> writes:
>>> On 05/09/2023 00:04, Keith Thompson wrote:
>>>> Bart <bc@freeuk.com> writes:
>>>> [...]
>>>>> All I know is that the family/dialect/standard in each case doesn't
>>>>> care amount making a missing 'return <value>' a hard error. So else
>>>>> are they being being lax over?
>>>> I have what I think is a very simple question for you.  Will you
>>>> acknowledge that the ISO C standard does not require a diagnostic
>>>> for a missing return statement in a non-void function?
>>>> I'm asking you for nothing more than a "yes" or "no" answer.  You
>>>> can
>>>> of course follow that with anything you like, but a "yes" or "no"
>>>> would be helpful -- or a brief explanation of why you think neither
>>>> "yes" nor "no" is a meaningful answer.
>>>> [...]
>> I note your refusal to answer this simple question.
>
> If you mean this:
>
>> Will you
> acknowledge that the ISO C standard does not require a diagnostic
> for a missing return statement in a non-void function?
>
> Then I don't know. I will have to take somebody's word for it. You
> seem to be implying the answer is Yes, so Yes.

You've written a C compiler.

I cannot imagine even trying to do that without referring to the ISO C
standard.

The answer to the question is yes.  The ISO C standard does not require a
diagnostic for a missing return statement in a non-void function.

I can post the URL of an appropriate draft of the standard, along with
specific citations that demonstrate that no such diagnostic is required.
But I probably won't bother, since you'll only complain about it and
pretend not to understand it.

> In my revised C compiler, I've taken out the -old option (it is now
> the default), and no longer bother to the extra check for a solid
> return value from a non-void function. Since nobody else cares, I'm
> not going to either, and you are now saying I can do that.

Why on Earth would you do that?  You have completely misunderstood this
discussion, apparently deliberately.  Such warnings are common, useful,
and permitted (though not required) by the ISO C standard.  I have not
said anything about what you can or cannot do with your own compiler.

Rejecting a program (as opposed to issuing a non-fatal warning) because
of a missing return statement would make your compiler non-conforming.
I do not care whether your compiler is conforming or not, and you've
made it clear that you don't either.

> (I may, however, need to insert an all-zeros return value in the
> generated code, since the IR is stack-based and that becomes more
> critical.)
>
> But both of the following are still hard errors:
>
>   int fred(void) {return;}
>   void bill(void) {return 1;}

Both of those are constraint violations, requiring a diagnostic from any
conforming C compiler.  Making them "hard errors" is a good idea.  It's
not much to brag about, but good for you.

-- 
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
Will write code for food.
void Void(void) { Void(); } /* The recursive call of the void */

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Re: bart again (UCX64) Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-01 18:55 +0000
  Re: bart again (UCX64) Bart <bc@freeuk.com> - 2023-09-01 21:27 +0100
    Re: bart again (UCX64) Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-01 20:46 +0000
      Re: bart again (UCX64) Bart <bc@freeuk.com> - 2023-09-01 22:29 +0100
        Re: bart again (UCX64) Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-01 22:19 +0000
          Re: bart again (UCX64) Bart <bc@freeuk.com> - 2023-09-03 13:56 +0100
            Re: bart again (UCX64) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-09-03 15:31 +0100
              Re: bart again (UCX64) Bart <bc@freeuk.com> - 2023-09-03 16:05 +0100
                Re: bart again (UCX64) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-09-04 03:17 +0100
                Re: bart again (UCX64) Bart <bc@freeuk.com> - 2023-09-04 10:34 +0100
                Re: bart again (UCX64) Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2023-09-04 03:07 -0700
                Re: bart again (UCX64) Bart <bc@freeuk.com> - 2023-09-04 11:43 +0100
                Re: bart again (UCX64) Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2023-09-04 04:21 -0700
                Re: bart again (UCX64) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-09-04 17:16 +0100
                Re: bart again (UCX64) Bart <bc@freeuk.com> - 2023-09-04 18:33 +0100
                Re: bart again (UCX64) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-09-05 01:33 +0100
                Re: bart again (UCX64) David Brown <david.brown@hesbynett.no> - 2023-09-04 15:27 +0200
                Re: bart again (UCX64) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-09-04 17:18 +0100
                Re: bart again (UCX64) Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-04 16:26 +0000
                Re: bart again (UCX64) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-09-04 19:33 +0100
                Re: bart again (UCX64) Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-04 19:17 +0000
                Re: bart again (UCX64) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-09-04 20:48 +0100
                Re: bart again (UCX64) Bart <bc@freeuk.com> - 2023-09-04 21:25 +0100
                Re: bart again (UCX64) Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-04 21:56 +0000
                Re: bart again (UCX64) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-09-05 01:34 +0100
                Re: bart again (UCX64) Bart <bc@freeuk.com> - 2023-09-04 21:06 +0100
                Re: bart again (UCX64) "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-09-04 13:09 -0700
                Re: bart again (UCX64) Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-09-04 16:04 -0700
                Re: bart again (UCX64) Bart <bc@freeuk.com> - 2023-09-05 00:52 +0100
                Re: bart again (UCX64) Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-09-04 17:16 -0700
                Re: bart again (UCX64) Bart <bc@freeuk.com> - 2023-09-05 15:33 +0100
                Re: bart again (UCX64) scott@slp53.sl.home (Scott Lurndal) - 2023-09-05 14:55 +0000
                Re: bart again (UCX64) Bobby Moore <bobbymoore018@gmail.com> - 2023-09-05 08:30 -0700
                Re: bart again (UCX64) David Brown <david.brown@hesbynett.no> - 2023-09-05 17:31 +0200
                Re: bart again (UCX64) Bart <bc@freeuk.com> - 2023-09-05 18:06 +0100
                Re: bart again (UCX64) Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-05 17:54 +0000
                Re: bart again (UCX64) David Brown <david.brown@hesbynett.no> - 2023-09-05 20:10 +0200
                Re: bart again (UCX64) Bart <bc@freeuk.com> - 2023-09-05 20:57 +0100
                Re: bart again (UCX64) David Brown <david.brown@hesbynett.no> - 2023-09-05 22:37 +0200
                Re: bart again (UCX64) Bart <bc@freeuk.com> - 2023-09-05 22:05 +0100
                Re: bart again (UCX64) Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-09-05 15:10 -0700
                Re: bart again (UCX64) Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-09-06 22:32 -0700
                Re: bart again (UCX64) Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-07 06:49 +0000
                Re: bart again (UCX64) David Brown <david.brown@hesbynett.no> - 2023-09-06 16:08 +0200
                Re: bart again (UCX64) Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2023-09-06 07:53 -0700
                Re: bart again (UCX64) David Brown <david.brown@hesbynett.no> - 2023-09-06 17:35 +0200
                Re: bart again (UCX64) Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2023-09-06 09:37 -0700
                Re: bart again (UCX64) David Brown <david.brown@hesbynett.no> - 2023-09-06 20:49 +0200
                Re: bart again (UCX64) scott@slp53.sl.home (Scott Lurndal) - 2023-09-06 19:51 +0000
                Re: bart again (UCX64) "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-09-06 12:52 -0700
                Re: bart again (UCX64) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-09-07 00:36 +0100
                Re: bart again (UCX64) Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-09-06 17:06 -0700
                Re: bart again (UCX64) Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2023-09-06 18:47 -0700
                Re: bart again (UCX64) David Brown <david.brown@hesbynett.no> - 2023-09-07 11:11 +0200
                Re: bart again (UCX64) Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2023-09-07 04:04 -0700
                Re: bart again (UCX64) David Brown <david.brown@hesbynett.no> - 2023-09-07 13:24 +0200
                Re: bart again (UCX64) Bart <bc@freeuk.com> - 2023-09-06 18:13 +0100
                Re: bart again (UCX64) David Brown <david.brown@hesbynett.no> - 2023-09-06 21:17 +0200
                Re: bart again (UCX64) Bart <bc@freeuk.com> - 2023-09-06 22:24 +0100
                Re: bart again (UCX64) David Brown <david.brown@hesbynett.no> - 2023-09-07 11:37 +0200
                Re: bart again (UCX64) Bart <bc@freeuk.com> - 2023-09-07 11:53 +0100
                Re: bart again (UCX64) David Brown <david.brown@hesbynett.no> - 2023-09-07 13:33 +0200
                Re: bart again (UCX64) Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-09-07 14:36 -0700
                Re: bart again (UCX64) Bart <bc@freeuk.com> - 2023-09-07 22:59 +0100
                Re: bart again (UCX64) Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-09-07 16:58 -0700
                Re: bart again (UCX64) Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-08 00:35 +0000
                Re: bart again (UCX64) Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-05 20:41 +0000
                Re: bart again (UCX64) Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-05 20:47 +0000
                Re: bart again (UCX64) Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-09-05 14:07 -0700
                Re: bart again (UCX64) Bart <bc@freeuk.com> - 2023-09-05 22:22 +0100
                Re: bart again (UCX64) Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-09-05 15:26 -0700
                Re: bart again (UCX64) Richard Damon <Richard@Damon-Family.org> - 2023-09-05 18:26 -0700
                Re: bart again (UCX64) James Kuyper <jameskuyper@alumni.caltech.edu> - 2023-09-07 23:15 -0400
                Re: bart again (UCX64) Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-09-05 13:48 -0700
                Re: bart again (UCX64) Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-05 21:36 +0000
                Re: bart again (UCX64) David Brown <david.brown@hesbynett.no> - 2023-09-05 13:24 +0200
                Re: bart again (UCX64) Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-09-04 15:46 -0700
        Re: bart again (UCX64) David Brown <david.brown@hesbynett.no> - 2023-09-02 17:44 +0200

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