From: Masamichi Hosoda <trueroad@trueroad.jp>
To: cygwin@cygwin.com
Subject: Re: `std::stod ("nan")` returns negative NaN
Date: Tue, 14 Aug 2018 01:10:00 -0000 [thread overview]
Message-ID: <20180814.100952.1684125661222835312.trueroad@trueroad.jp> (raw)
In-Reply-To: <CANnLRdii8mX71D936AhhEYm+S0s4gS5RGgpPhV_rB6=kzmXKsw@mail.gmail.com>
> On Mon, 13 Aug 2018 at 19:46, Duncan Roe <duncan_roe@optusnet.com.au> wrote:
>>
>> On Mon, Aug 13, 2018 at 12:52:48PM -0400, Stephen John Smoogen wrote:
>> > On Mon, 13 Aug 2018 at 11:16, Masamichi Hosoda <trueroad@trueroad.jp> wrote:
>> [...]
>> > On Fedora 27 with 7.3.1 it gives
>> > ```
>> > stod ("nan") = nan
>> > stod ("-nan") = nan
>> > quiet_NaN () = nan
>> > ```
>> [...]
>
> I tested a compile on Windows Subsystem for Linux Ubuntu 18.04 which
> had gcc 7.3.0. The output was the same as everything but Cygwin. At
> this point it is time to pull through the gdb debugger and try to
> figure out where it is coming from.
I suspect `cygwin1.dll`'s `strtod ()` etc.
Here's a code.
```
/* gcc foobar.c */
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
int main (void)
{
printf ("strtod (\"nan\", NULL) = %f\n", strtod ("nan", NULL));
printf ("strtod (\"-nan\", NULL) = %f\n", strtod ("-nan", NULL));
printf ("nan (\"\") = %f\n", nan (""));
return 0;
}
```
Cygwin 2.10.0 64 bit with gcc 7.3.0
```
strtod ("nan", NULL) = -nan
strtod ("-nan", NULL) = nan
nan ("") = nan
```
Ubuntu 16.04 LTS 64 bit with gcc 5.4.0
```
strtod ("nan", NULL) = nan
strtod ("-nan", NULL) = nan
nan ("") = nan
```
--
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
next prev parent reply other threads:[~2018-08-14 1:10 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-13 15:16 Masamichi Hosoda
2018-08-13 16:53 ` Stephen John Smoogen
2018-08-13 23:46 ` Duncan Roe
2018-08-14 0:46 ` Stephen John Smoogen
2018-08-14 1:10 ` Masamichi Hosoda [this message]
2018-08-14 2:31 ` strtod ("nan") returns negative NaN (was `std::stod ("nan")` returns negative NaN) Masamichi Hosoda
2018-08-14 3:25 ` strtod ("nan") returns negative NaN Steven Penny
2018-08-14 4:46 ` Masamichi Hosoda
2018-08-14 9:56 ` Corinna Vinschen
2018-08-14 10:39 ` Corinna Vinschen
2018-08-14 12:18 ` Masamichi Hosoda
2018-08-14 13:23 ` Corinna Vinschen
2018-08-14 13:41 ` Stephen John Smoogen
2018-08-14 15:25 ` Heavenly Avenger
2018-08-14 15:54 ` Corinna Vinschen
2018-08-14 17:08 ` Heavenly Avenger
2018-08-14 16:05 ` Masamichi Hosoda
2018-08-14 19:24 ` Steven Penny
2018-08-14 21:45 ` Andy Moreton
2018-08-14 22:23 ` Stephen John Smoogen
2018-08-15 0:02 ` Eric Blake
2018-08-15 7:36 ` Steven Penny
2018-08-21 3:18 ` Brian Inglis
2018-08-14 19:44 ` Achim Gratz
2018-08-21 13:28 ` Brian Inglis
2018-08-14 15:05 ` Masamichi Hosoda
2018-08-14 15:21 ` Masamichi Hosoda
2018-08-14 15:35 ` Heavenly Avenger
2018-08-14 20:05 ` Joseph Myers
2018-08-14 20:19 ` Joseph Myers
2018-08-15 8:51 ` Masamichi Hosoda
2018-08-15 12:55 ` Masamichi Hosoda
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180814.100952.1684125661222835312.trueroad@trueroad.jp \
--to=trueroad@trueroad.jp \
--cc=cygwin@cygwin.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).