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Re: printf and time_t

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James Kuyper <jameskuyper@alumni.caltech.edu> writes:
> Tim Rentsch <tr.17687@z991.linuxsc.com> writes:
[...]
>> Besides all of that, _Imaginary types don't satisify the condition
>> for time_t to be an arithmetic type.  Annex G says the imaginary
>> types are floating types, but in C99 Annex G is informative, not
>> normative.
>
> True, but if _Imaginary types are supported by an implementation, Annex
> G describes what it is that is being supported. I don't see a problem,
> though I'm sure that you do.
> I hadn't remembered that the imaginary types were removed from the draft
> version of C202X. They were still present in n3220.pdf, dated 2024. In
> that version, Annex G (which describes imaginary types) is described as
> normative. 7.3.1p6 indicates that they were optional in that version.
> However, if they were supported, they did meet the requirements of an
> arithmetic type.

I don't have the official ISO C23 standard, but I understand
that N3220 is quite close to it.  In that draft, and I believe
in the actual standard, Annex G is normative but optional.
Implementations are not required to support it unless they
define __STDC_IEC_559_COMPLEX__.  (C23 changes the macro
name to  __STDC_IEC_60559_COMPLEX__ and makes the name
__STDC_IEC_559_COMPLEX__ obsolescent.)

C11 and C17 are similar.

(As of C23, Annex G still says "There is a new keyword _Imaginary".
It's hardly new; it goes back to C99.)

As I understand it, a conforming implementation that defines
__STDC_IEC_559_COMPLEX__ or __STDC_IEC_60559_COMPLEX__ *must*
implement both complex and imaginary types.  Neither gcc nor clang
does so.

C2y completely drops support for imaginary types.

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

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Re: printf and time_t Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-01-07 05:02 -0800
  Re: printf and time_t "James Russell Kuyper Jr." <jameskuyper@alumni.caltech.edu> - 2026-01-07 12:58 -0500
    Re: printf and time_t Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-03-01 23:21 -0800
      Re: printf and time_t Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2026-03-02 03:37 -0800
      Re: printf and time_t James Kuyper <jameskuyper@alumni.caltech.edu> - 2026-03-02 17:53 -0500
        Re: printf and time_t Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2026-03-02 18:04 -0800

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