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Re: a MSVC and glibc-compatible fmod()

From Michael S <already5chosen@yahoo.com>
Newsgroups comp.lang.c++
Subject Re: a MSVC and glibc-compatible fmod()
Date 2025-03-11 13:34 +0200
Organization A noiseless patient Spider
Message-ID <20250311133458.00003aa2@yahoo.com> (permalink)
References (15 earlier) <vqnqft$1j90u$1@raubtier-asyl.eternal-september.org> <vqnqpd$1j9nq$1@raubtier-asyl.eternal-september.org> <vqoshu$1sohk$1@raubtier-asyl.eternal-september.org> <20250311122902.00002d8b@yahoo.com> <vqp5qv$1udlb$1@raubtier-asyl.eternal-september.org>

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On Tue, 11 Mar 2025 12:12:31 +0100
Bonita Montero <Bonita.Montero@gmail.com> wrote:

> Am 11.03.2025 um 11:29 schrieb Michael S:
> 
> > Pay attention that fmod() has no requirements w.r.t. to such
> > exceptions as FE_INEXACT, FE_UNDERFLOW and non-standard
> > FE_DENORMAL.  
> 
> Yes, that's while I evaluate FE_INVALID only. But your code also can
> set FE_INEXACT due to your "rounding" with sign change. MSVC seems
> also try to do the math with the FPU with a integer-fallback, because
> with exponent differences <= 53 MSVC's fmod() often sets FE_INECACT;
> but I ignore that because that shouldn't be part of fmod();
> 
> > Strictly speaking, even raising FE_OVERFLOW is not illegal,
> > but doing so would be bad quality of implementation.  
> 
> Couldn't FE_OVERFLOW happen with your implementation when the
> exponents are too far away that you get inf from the division ?
>

It couldn't happen. Loop within loop exists for this reason exactly: to
prevent overflow.

> > Also spec does not say what happens to FE_INVALID when one of the
> > inputs is signalling NAN.  
> 
> See my code; I return MSVC and glibc compatible NaNs and I return
> the same exceptions. MSVC sets FE_INVALID only when x is inf or y
> is zero, glibc in addition raises FE_INVALID when either operand
> is a signalling NaN.
> 

Exactly. Both options are legal. MS's decision to not set FE_INVALID is
as good as glibc decision to set it.
So, test bench should accept both variants as correct.
BTW, what is the output of MS library in that case? SNAN or QNAN?
I would think that it should be SNAN even when the other argument is
QNAN. But even that is probably not required by the Standard.

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a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-02-24 11:48 +0100
  Re: a MSVC and glibc-compatible fmod() Muttley@DastardlyHQ.org - 2025-02-24 12:00 +0000
    Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-02-24 13:48 +0100
      Re: a MSVC and glibc-compatible fmod() Muttley@DastardlyHQ.org - 2025-02-24 13:09 +0000
        Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-02-24 14:22 +0100
          Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-02-24 17:13 +0200
            Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-02-24 16:19 +0100
              Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-02-24 17:52 +0200
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-02-25 09:09 +0100
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-02-25 16:17 +0100
                Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-02-25 17:26 +0200
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-02-25 16:45 +0100
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-02-25 16:57 +0100
                Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-02-25 19:17 +0200
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-02-25 18:58 +0100
                Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-02-26 00:36 +0200
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-02-26 04:15 +0100
                Re: a MSVC and glibc-compatible fmod() Muttley@DastardlyHQ.org - 2025-02-26 08:16 +0000
                Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-02-26 14:27 +0200
                Re: a MSVC and glibc-compatible fmod() Muttley@DastardlyHQ.org - 2025-02-26 14:39 +0000
                FP_CONTRACT was : a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-02-28 16:28 +0200
                Re: FP_CONTRACT was : a MSVC and glibc-compatible fmod() Tim Rentsch <tr.17687@z991.linuxsc.com> - 2025-03-01 08:35 -0800
        Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-02-24 16:22 +0200
          Re: a MSVC and glibc-compatible fmod() Muttley@DastardlyHQ.org - 2025-02-24 15:10 +0000
            Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-02-24 17:33 +0200
              Re: a MSVC and glibc-compatible fmod() Muttley@DastardlyHQ.org - 2025-02-24 16:48 +0000
  Re: a MSVC and glibc-compatible fmod() Mr Flibble <leigh@i42.co.uk> - 2025-02-24 22:21 +0000
    Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-02-25 07:37 +0100
      Re: a MSVC and glibc-compatible fmod() Mr Flibble <leigh@i42.co.uk> - 2025-02-25 23:03 +0000
        Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-02-26 02:00 +0200
        Re: a MSVC and glibc-compatible fmod() Wuns Haerst <Wuns.Haerst@wurstfabrik.at> - 2025-02-26 04:01 +0100
    Re: a MSVC and glibc-compatible fmod() Muttley@DastardlyHQ.org - 2025-02-25 08:24 +0000
  Re: a MSVC and glibc-compatible fmod() Mr Flibble <leigh@i42.co.uk> - 2025-02-27 21:16 +0000
    Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-02-28 07:59 +0100
    Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-02-28 12:35 +0200
      Re: a MSVC and glibc-compatible fmod() Mr Flibble <leigh@i42.co.uk> - 2025-02-28 18:12 +0000
    Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-02-28 19:23 +0100
  Re: a MSVC and glibc-compatible fmod() Mr Flibble <leigh@i42.co.uk> - 2025-02-28 18:30 +0000
    Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-02-28 19:31 +0100
      Re: a MSVC and glibc-compatible fmod() Mr Flibble <leigh@i42.co.uk> - 2025-02-28 19:47 +0000
        Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-02-28 20:49 +0100
          Re: a MSVC and glibc-compatible fmod() Mr Flibble <leigh@i42.co.uk> - 2025-03-01 14:37 +0000
            Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-01 16:58 +0100
              Re: a MSVC and glibc-compatible fmod() Mr Flibble <leigh@i42.co.uk> - 2025-03-01 17:11 +0000
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-01 21:02 +0100
                Re: a MSVC and glibc-compatible fmod() Mr Flibble <leigh@i42.co.uk> - 2025-03-01 20:32 +0000
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-01 21:37 +0100
                Re: a MSVC and glibc-compatible fmod() Mr Flibble <leigh@i42.co.uk> - 2025-03-01 20:45 +0000
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-02 09:40 +0100
  Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-01 22:55 +0200
    Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-02 18:54 +0200
      Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-02 17:59 +0100
  Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-02 15:41 +0200
    Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-02 17:10 +0100
      Re: a MSVC and glibc-compatible fmod() Mr Flibble <leigh@i42.co.uk> - 2025-03-02 16:22 +0000
        Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-02 17:26 +0100
          Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-02 19:07 +0200
            Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-02 18:09 +0100
              Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-02 18:11 +0100
                Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-02 19:52 +0200
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-02 18:55 +0100
                Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-02 20:09 +0200
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-02 19:14 +0100
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-02 19:57 +0100
                Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-02 22:58 +0200
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-03 12:52 +0100
                Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-03 18:10 +0200
                Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-03 23:55 +0200
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-07 09:51 +0100
                Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-03 18:20 +0200
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-03 17:30 +0100
                Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-03 19:27 +0200
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-03 18:39 +0100
                Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-03 02:01 +0200
        Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-02 19:37 +0200
          Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-02 18:41 +0100
            Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-02 20:00 +0200
              Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-02 19:01 +0100
      Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-09 01:31 +0200
        Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-09 07:41 +0100
          Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-09 11:08 +0200
            Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-09 10:31 +0100
              Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-09 11:46 +0200
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-09 10:54 +0100
                Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-09 12:09 +0200
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-09 11:21 +0100
                Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-09 14:09 +0200
                Re: a MSVC and glibc-compatible fmod() Mr Flibble <leigh@i42.co.uk> - 2025-03-09 15:26 +0000
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-09 17:02 +0100
                Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-09 19:55 +0200
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-09 19:10 +0100
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-09 19:27 +0100
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-09 17:23 +0100
                Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-09 20:04 +0200
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-09 19:11 +0100
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-09 20:11 +0100
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-10 07:24 +0100
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-10 10:46 +0100
                Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-10 14:26 +0200
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-10 13:45 +0100
                Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-10 16:33 +0200
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-10 15:46 +0100
                Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-10 16:59 +0200
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-10 16:11 +0100
                Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-10 17:43 +0200
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-10 17:13 +0100
                Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-10 19:51 +0200
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-10 19:00 +0100
                Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-10 20:38 +0200
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-10 22:34 +0100
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-10 22:36 +0100
                Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-11 12:47 +0200
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-10 23:52 +0100
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-10 23:57 +0100
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-11 09:34 +0100
                Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-11 12:29 +0200
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-11 12:12 +0100
                Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-11 13:34 +0200
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-11 13:10 +0100
                Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-11 14:55 +0200
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-11 14:08 +0100
                Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-11 15:46 +0200
                Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-11 13:51 +0200
                Re: a MSVC and glibc-compatible fmod() James Kuyper <jameskuyper@alumni.caltech.edu> - 2025-03-11 14:21 -0400
                Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-11 20:28 +0200
                Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-16 13:48 +0200
                Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-10 13:17 +0200
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-10 12:53 +0100
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-10 12:54 +0100
              Re: a MSVC and glibc-compatible fmod() wij <wyniijj5@gmail.com> - 2025-03-09 18:51 +0800
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-09 12:56 +0100
                Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-09 14:23 +0200
                Re: a MSVC and glibc-compatible fmod() Bonita Montero <Bonita.Montero@gmail.com> - 2025-03-09 13:39 +0100
                Re: a MSVC and glibc-compatible fmod() Michael S <already5chosen@yahoo.com> - 2025-03-09 14:56 +0200

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