X-Recipient:	archive-cygwin AT delorie DOT com
DomainKey-Signature:	a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id
	:list-unsubscribe:list-subscribe:list-archive:list-post
	:list-help:sender:mime-version:references:in-reply-to:from:date
	:message-id:subject:to:cc:content-type; q=dns; s=default; b=Vv+N
	yWXus7+XTLd1M044pB9x7NQLVOpMJA1B6ZQZpYuG8nZxRdJdLpq1MOq7MLsV92N4
	+BBnF1ETBo8tC+v5hjgtAOWFk05+95/NSDW/TJVS0/lYLU/msmvj2C21rxpcFU1M
	znCvHac3AUqaTxVAI+O3/YC9uxoBWsIxyMsvk+I=
DKIM-Signature:	v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id
	:list-unsubscribe:list-subscribe:list-archive:list-post
	:list-help:sender:mime-version:references:in-reply-to:from:date
	:message-id:subject:to:cc:content-type; s=default; bh=ZYUuTqgVtm
	OhQPMBGkG536GOafg=; b=KUjR0Cqi0H7Hf/r+VJGEdLwOroJfaQUpwJn3EG7FCS
	bKSNk5cWPZm5O4vN4wZoJyVRsevGV1pzauaxEmZ98f+qa69dgwRI+CVtyVtB4yst
	TvXS0MlVfC5uIm/KaHmR0wOcHxUxTb66+ZEKdyi41e/53fDfK/fzXaAafGl6RG0h
	w=
Mailing-List:	contact cygwin-help AT cygwin DOT com; run by ezmlm
List-Id:	<cygwin.cygwin.com>
List-Subscribe:	<mailto:cygwin-subscribe AT cygwin DOT com>
List-Archive:	<http://sourceware.org/ml/cygwin/>
List-Post:	<mailto:cygwin AT cygwin DOT com>
List-Help:	<mailto:cygwin-help AT cygwin DOT com>, <http://sourceware.org/ml/#faqs>
Sender:	cygwin-owner AT cygwin DOT com
Mail-Followup-To:	cygwin AT cygwin DOT com
Delivered-To:	mailing list cygwin AT cygwin DOT com
Authentication-Results:	sourceware.org; auth=none
X-Spam-SWARE-Status:	No, score=-1.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_NONE,SPF_PASS autolearn=ham version=3.3.2 spammy=H*Ad:D*jp, HX-HELO:sk:mail-pf, H*r:sk:mail-pf
X-HELO:	mail-pf1-f176.google.com
DKIM-Signature:	v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=MPAtezmUCiZ/TsRGr2Lf4Z+Mwlr+P3nM8Je/j7LoWoo=; b=He5GgI4cHV9vvqCx9S3BZ3bAsdsQZIm5meAtXJoC1grtdtIDiQv7YKlok2umQ9A+YC bHZ2oM1kVn0gSIBpPPlORg2+HQEVdEqzi64r+3T1P4UJW7+qs1TzC7cbUdHjrqZJ5iYW DNFPEYri3o1kUm6uYVQEJRc7bbUgBZFV7v0jgfjZAswtp/rtoJSz+SYQjva/tPOpYNxr dSUyLI+510Ey0bzGyf5JxdLX+1iwXbb4AEwFwa7q5C61bBAk8djIXSnVbY/o9rerk1t5 /IkK8JU3tfOAkMNszXzSbInWzTs0/7GIC51XxGaSSQBHan+3SvHpuyrQDHNVAVcC2lSM 7ytQ==
MIME-Version:	1.0
References:	<20180814 DOT 001550 DOT 1040828527127506667 DOT trueroad AT trueroad DOT jp>
In-Reply-To:	<20180814.001550.1040828527127506667.trueroad@trueroad.jp>
From:	Stephen John Smoogen <smooge AT gmail DOT com>
Date:	Mon, 13 Aug 2018 12:52:48 -0400
Message-ID:	<CANnLRdifQXhm9wKahU78BN+4FCeXgcFOgFbzNzNbJbH8AOwZoA@mail.gmail.com>
Subject:	Re: `std::stod ("nan")` returns negative NaN
To:	cygwin AT cygwin DOT com
Cc:	trueroad AT trueroad DOT jp
X-IsSubscribed:	yes

On Mon, 13 Aug 2018 at 11:16, Masamichi Hosoda <trueroad AT trueroad DOT jp> wrote:
>
> Hi
>
> I've found a curious behavior about `std::stod ("nan")` on Cygwin.
> Only on Cygwin, `std::stod ("nan")` returns negative NaN.
> On Linux etc., `std::stod ("nan")` returns positive NaN.
>
> Here is a reproduction code.
>
> ```
> // g++ -std=c++11 foobar.cc
>
> #include <iostream>
> #include <limits>
> #include <string>
>
> int main ()
> {
>   std::cout << "stod (\"nan\") = "
>             << std::stod ("nan")
>             << std::endl;
>   std::cout << "stod (\"-nan\") = "
>             << std::stod ("-nan")
>             << std::endl;
>
>   std::cout << "quiet_NaN () = "
>             << std::numeric_limits<double>::quiet_NaN ()
>             << std::endl;
> }
> ```
>
> The result on Cygwin 2.10.0 64 bit (g++ 7.3.0):
> ```
> stod ("nan") = -nan
> stod ("-nan") = nan
> quiet_NaN () = nan
> ```
>

On Fedora 27 with 7.3.1 it gives
```
stod ("nan") = nan
stod ("-nan") = nan
quiet_NaN () = nan
```
So it looks like it is a library problem of some sort.

> The result on MinGW-w64 64 bit (g++ 4.9.2):
> ```
> stod ("nan") = nan
> stod ("-nan") = nan
> quiet_NaN () = nan
> ```
>
> The result on Ubuntu 16.04 LTS 64 bit (g++ 5.4.0):
> ```
> stod ("nan") = nan
> stod ("-nan") = nan
> quiet_NaN () = nan
> ```
>
> The result on FreeBSD 10.1 64 bit (clang++ 3.4.1):
> ```
> stod ("nan") = nan
> stod ("-nan") = nan
> quiet_NaN () = nan
> ```
>
> Is it correct that returning negative NaN on Cygwin?
>
> Thanks.
>
> --
> Problem reports:       http://cygwin.com/problems.html
> FAQ:                   http://cygwin.com/faq/
> Documentation:         http://cygwin.com/docs.html
> Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple
>


-- 
Stephen J Smoogen.

--
Problem reports:       http://cygwin.com/problems.html
FAQ:                   http://cygwin.com/faq/
Documentation:         http://cygwin.com/docs.html
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple

- Raw text -