DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 6D9163951840
To: cygwin@cygwin.com
Subject: Re: sqrtl behavior inconsistent with sqrt and sqrtf
Date: Tue, 27 Oct 2020 07:44:32 -0400
Message-ID: <vriuh7qf28rj.fsf@mail.aol.com>
References: <vriulffr2a1e.fsf@mail.aol.com>
Mime-Version: 1.0
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (cygwin)
Cancel-Lock: sha1:6De5zZEQer7fcV1F/onMPDfsOO4=
From: airplanemath via Cygwin <cygwin@cygwin.com>
Reply-To: airplanemath <airplanemath@aol.com>
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Sender: "Cygwin" <cygwin-bounces@cygwin.com>

airplanemath via Cygwin <cygwin@cygwin.com> writes:

> Compiling and running the attached program with the command line below
> produces the output below:
>
> $ gcc -O0 -Og test_sqrt.c -o test_sqrt && ./test_sqrt
> Long double: -inf -inf
> Double:      -inf -nan
> Float:       -inf -nan
>
> I suspect the behavior for long double should be the same as for double
> and float (sqrt(-inf) = nan), but I'm not sure where to change that.
> I'm running a snapshot of Cygwin 3.2.0, if that's important.

The mail archive says I'm bad at attaching things.
Program source included below:

#include <math.h>
#include <stdio.h>

int main() {
  long double a, b;
  double c, d;
  float f, g;
  a = (long double) -INFINITY;
  c = (double) -INFINITY;
  f = (float) -INFINITY;
  b = sqrtl(a);
  d = sqrt(c);
  g = sqrtf(f);
  printf("Long double: %4Lf %4Lf\n", a, b);
  printf("Double:      %4lf %4lf\n", c, d);
  printf("Float:       %4f %4f\n", f, g);
  return 0;
}

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