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From: Tim Rentsch <tr.17687@z991.linuxsc.com>
Newsgroups: comp.lang.c
Subject: Re: "Catch-23: The New C Standard,Sets the World on Fire" by Terence Kelly with Special Guest Borer Yekai Pan
Date: Wed, 05 Apr 2023 09:20:22 -0700
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Ben Bacarisse <ben.usenet@bsb.me.uk> writes:

> Lowell Gilbert <lgusenet@be-well.ilk.org> writes:

[earlier context]

>>>>>> "Catch-23:  The New C Standard,Sets the World on Fire" 
>>>>>>     https://queue.acm.org/detail.cfm?id=3588242
>>>>>> [snip]
>>>>>
>> I think they're saying that before C17, realloc to a size of zero
>> was implementation defined, and that C17 changed that to it being
>> undefined.  That isn't quite right, because it was
>> implementation-defined both before and after.  But (I think;  I
>> don't have a full copy of C17 at hand) the limitations were
>> changed, and realloc to a size of zero was explicitly described as
>> obsolescent.  Unless I'm mistaken factually (possible, as I
>> mentioned) I think it's reasonable to consider C17 to be moving
>> towards disallowing the behaviour.
>
> I only have a draft of C17.  The fact that C standards cost a lot of
> money is a valid point.  I can't justify paying anything just to be
> able to chat on comp.lang.c about some finer points.
>
> The draft I have suggests that C17 just codified what implementation
> currently do:  [...]

I think you can find the C17 information you're looking for by
looking at these two documents:

    https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2464.pdf
    https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2438.htm