strtod ("nan") returns negative NaN (was `std::stod ("nan")` returns negative NaN)

2018-08-13 Thread Masamichi Hosoda
>> On Mon, 13 Aug 2018 at 19:46, Duncan Roe 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 >>> > wrote: >>> [...] >>> > On Fedora 27 with 7.3.1 it gives >>> > ``` >>> > stod ("nan") = nan >>> > stod ("-nan

Re: `std::stod ("nan")` returns negative NaN

2018-08-13 Thread Masamichi Hosoda
> On Mon, 13 Aug 2018 at 19:46, Duncan Roe 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 >> > wrote: >> [...] >> > On Fedora 27 with 7.3.1 it gives >> > ``` >> > stod ("nan") = nan >> > stod ("-nan") = nan >

Re: `std::stod ("nan")` returns negative NaN

2018-08-13 Thread Stephen John Smoogen
On Mon, 13 Aug 2018 at 19:46, Duncan Roe 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 wrote: > [...] > > On Fedora 27 with 7.3.1 it gives > > ``` > > stod ("nan") = nan > > stod ("-nan") = nan > > quiet_NaN ()

Re: `std::stod ("nan")` returns negative NaN

2018-08-13 Thread Duncan Roe
On Mon, Aug 13, 2018 at 12:52:48PM -0400, Stephen John Smoogen wrote: > On Mon, 13 Aug 2018 at 11:16, Masamichi Hosoda wrote: [...] > On Fedora 27 with 7.3.1 it gives > ``` > stod ("nan") = nan > stod ("-nan") = nan > quiet_NaN () = nan > ``` [...] Same with Slackware 14.2 / gcc (GCC) 5.3.0 -- P

Re: `std::stod ("nan")` returns negative NaN

2018-08-13 Thread Stephen John Smoogen
On Mon, 13 Aug 2018 at 11:16, Masamichi Hosoda 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")`

`std::stod ("nan")` returns negative NaN

2018-08-13 Thread Masamichi Hosoda
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 #inc