Re: [PATCH 3/4] use exact types for the [U]INTXX_C macros

[Jens Gustedt <jens.gustedt@inria.fr>]

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Am Dienstag, den 02.12.2014, 19:01 -0500 schrieb Rich Felker:
> On Tue, Dec 02, 2014 at 10:37:54PM +0100, Jens Gustedt wrote:
> > These are DR 209 and 456
> > 
> > http://www.open-std.org/jtc1/sc22/wg14/www/docs/dr_209.htm
> > http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1892.htm#dr_456
> 
> I don't see where your interpretation is clear from these. DR 209
> added the text I cited. It's not clear what the change made to
> 7.18.4.1 is (I don't have the old text in front of me) so perhaps you
> could shed some light on why you think it requires the odd types.

I also only have the corrected version in front, but I vaguely
remember that the change was from types [u]intXX_t to [u]int_leastXX_t
because the macros are supposed to exist, even if the corresponding
[u]intXX_t doesn't.

> DR 456 just seems to state that DR 209 already adequately handled the
> situation and that no further change is needed.

exactly, furthermore they add

   The committee believes that DR209 is still appropriate in that
   "compiler magic" must be used for the implementation of these
   macros. The committee does not consider this a defect.

The part about the compiler magic is completely senseless when
supposing that the constants promote.

In addition, from discussion on the WG14 mailing list I see that
people there expect the macros to resolve to the unpromoted type when
used in _Generic.

And isn't all of this just the purpose of these macros? If we'd
suppose they promote, standard literals to denote the constants would
mainly suffice: they already do the right thing for narrow types,
namely promotion.

Jens

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