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From: Tim Rentsch <tr.17687@z991.linuxsc.com>
Newsgroups: comp.lang.c
Subject: Re: Loops (was Re: do { quit; } else { })
Date: Mon, 12 May 2025 07:19:00 -0700
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Keith Thompson <Keith.S.Thompson+u@gmail.com> writes:

> Tim Rentsch <tr.17687@z991.linuxsc.com> writes:
>
>> Keith Thompson <Keith.S.Thompson+u@gmail.com> writes:
>>
>>> Tim Rentsch <tr.17687@z991.linuxsc.com> writes:
>>>
>>>> Keith Thompson <Keith.S.Thompson+u@gmail.com> writes:
>>>>
>>>>> James Kuyper <jameskuyper@alumni.caltech.edu> writes:
>>>>> [...]
>>>>>
>>>>>> It's main potential usefulness is not in the definition of the
>>>>>> function, but in calls to the function.  If the calls occur in
>>>>>> a different translation unit from the definition, the compiler
>>>>>> does not have the needed information.
>>>>>
>>>>> It does if the visible declaration has the same information.
>>>>
>>>> Like 'restrict', parameter array length information, specified by
>>>> way of 'static', is ignored outside of function definitions.  As
>>>> was intended (with 'restrict' also).
>>>
>>> I think that by "is ignored", you mean that compilers are not
>>> required to pay attention to it.  [...]
>>
>> I mean it has no effect on program semantics.
>
> It affects whether a program has defined or undefined behavior.
> (Yes, a conforming compiler could ignore it.)

Please read again what I said:  parameter array length information,
specified by way of 'static', is ignored _outside of function
definitions_.

>>>> Furthermore, and also like 'restrict', there is no general
>>>> way to verify at compile time that the stipulated condition
>>>> holds.
>>>
>>> Right, but that doesn't prevent implementations from issuing
>>> useful warnings when it can determine that the stipulated
>>> condition does not hold.
>>
>> True, but in many cases they can't, because that information
>> is not part of the function's type and so often it is not
>> present.
>
> Why would it not be present?
>
> If you mean that someone might use `[static N]` in a function's
> definition but not in a declaration, sure, but I would always
> make sure they match as closely as possible. [...]

It strikes me that you have a rather self-centered view of the
world.  The vast majority of all C code is written by people other
than yourself.

>>>> Considering the above, it's better to observe the status quo, and
>>>> leave any diagnostics up to the discretion of the implementation,
>>>> rather than try to retrofit an incompatible change that would
>>>> make an infringement be a constraint violation that can't be
>>>> checked anyway.
>>>
>>> Observing the status quo is better than what, exactly?
>>
>> Better than than trying to retrofit an incompatible change that
>> would make an infringement be a constraint violation that can't
>> be checked anyway.
>
> And as you seem to have agreed, nobody suggested that.  Were we
> supposed to guess what it's better than?  Or did I miss something?

There was no reason to guess, because it was written in plain
English in the earlier posting.