Re: Footnote in section on Address-Of Operator

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From	Tim Rentsch <tr.17687@z991.linuxsc.com>
Newsgroups	comp.std.c
Subject	Re: Footnote in section on Address-Of Operator
Date	Wed, 23 Nov 2022 18:48:40 -0800
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Ben Bacarisse <ben.usenet@bsb.me.uk> writes:

> JoJoModding <jojohostert@gmail.com> writes:
>
>> in the paragraph on address and indirection operators (6.5.3.2 in the
>> C23 draft N3047), there is a footnote (footnote 117 in that draft),
>> which says that
>>
>>> &*E is equivalent to E (even if E is a null pointer)
>
> This seems to be a case where a footnote might add confusion rather than
> clarity.  The normative text makes it clear that &*E can't be equivalent
> to E in every way because &*E is not an lvalue.  And &*E has type
> constraints that E does not have.
>
>> This seems to imply that sizeof(&*E) == sizeof(E), which is unexpected
>> if E is an array.
>
> There are much simpler examples if the apparent non-equivalence.  If p
> is a pointer object, p can be assigned to by &*p can't be.  And due to
> the clause about constraints.  &*(void *)0 is a constraint violation,
> but (void *)0 is obviously fine.

What makes you say &*(void*)0 is a constraint violation?  I
don't see any constraints that are violated.

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Footnote in section on Address-Of Operator JoJoModding <jojohostert@gmail.com> - 2022-11-23 14:40 -0800
  Re: Footnote in section on Address-Of Operator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-11-24 00:05 +0000
    Re: Footnote in section on Address-Of Operator Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-11-23 18:48 -0800
      Re: Footnote in section on Address-Of Operator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-11-24 13:26 +0000

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