220 37676 article Path: news.gmane.org!.POSTED!not-for-mail From: Hyman Rosen Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Why do we need `volatile` in C++? 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[209.85.220.41]) by mx.google.com with SMTPS id n25sor1915844wmh.35.2018.04.05.12.34.27 for (Google Transport Security); Thu, 05 Apr 2018 12:34:27 -0700 (PDT) Received-SPF: pass (google.com: domain of hyman.rosen@gmail.com designates 209.85.220.41 as permitted sender) client-ip=209.85.220.41; X-Received: by 10.28.101.6 with SMTP id z6mr10346931wmb.110.1522956866395; Thu, 05 Apr 2018 12:34:26 -0700 (PDT) Original-Received: by 10.28.85.201 with HTTP; Thu, 5 Apr 2018 12:34:05 -0700 (PDT) In-Reply-To: <5AC66322.50207@gmx.net> X-Original-Sender: hyman.rosen@gmail.com X-Original-Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=ZCuDtt/b; spf=pass (google.com: domain of hyman.rosen@gmail.com designates 209.85.220.41 as permitted sender) smtp.mailfrom=hyman.rosen@gmail.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Spam-Checked-In-Group: std-proposals@isocpp.org X-Google-Group-Id: 399137483710 List-Post: , List-Help: , List-Archive: List-Subscribe: , List-Unsubscribe: , Xref: news.gmane.org gmane.comp.lang.c++.isocpp.proposals:37676 Archived-At: --001a114b332c07a35305691f0705 Content-Type: text/plain; charset="UTF-8" On Thu, Apr 5, 2018 at 1:55 PM, Jens Maurer wrote: > > What normative statement in the standard makes you believe that > "casting to a floating-point type [...] must do the downscaling"? In N4700, [expr]/13 says *The values of the floating operands and the results of floating expressionsmay be represented in greater * *precision and range than that required bythe type; the types are not changed thereby.64* The associated footnote says *64) The cast and assignment operators must still perform their specificconversions as described in 8.4, 8.2.9 and 8.18.* -- You received this message because you are subscribed to the Google Groups "ISO C++ Standard - Future Proposals" group. To unsubscribe from this group and stop receiving emails from it, send an email to std-proposals+unsubscribe@isocpp.org. To post to this group, send email to std-proposals@isocpp.org. To view this discussion on the web visit https://groups.google.com/a/isocpp.org/d/msgid/std-proposals/CAHSYqdYF3mSv99Z0r68j4Ser8i7XVtbEC0M2gdKVCvOd5ugUAQ%40mail.gmail.com. --001a114b332c07a35305691f0705 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
On T= hu, Apr 5, 2018 at 1:55 PM, Jens Maurer <Jens.Maurer@gmx.net> wrote:
What normative statement in the standard makes you believe that
"casting to a floating-point type [...] must do the downscaling"?=

In N4700, [expr]/13 says
The values of the floa= ting operands and the results of floating expressions
may be represented= in greater=C2=A0precision and range than that required by
the ty= pe; the types are not changed thereby.64=

The associated footnote says
64) The cast and assignment operators must still perform their specif= ic
conversions as described in 8.4, 8.2.9 and 8.18.
=

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