tests/test-nextafter.c

   1 /* Test of nextafter() function.
   2    Copyright (C) 2010-2024 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation, either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 /* Written by Bruno Haible <bruno@clisp.org>, 2010.  */
  18
  19 #include <config.h>
  20
  21 #include <math.h>
  22
  23 #include "signature.h"
  24 SIGNATURE_CHECK (nextafter, double, (double, double));
  25
  26 #include "macros.h"
  27
  28 volatile double x;
  29 double y;
  30
  31 int
  32 main ()
  33 {
  34   /* A particular value.  */
  35   x = 1.628947572;
  36   /* Towards 0.  */
  37   y = nextafter (x, 0);
  38   ASSERT (y < x);
  39   ASSERT (y > 1.628947571);
  40   y = nextafter (y, x + x);
  41   ASSERT (y == x);
  42   /* Towards infinity.  */
  43   y = nextafter (x, x + x);
  44   ASSERT (y > x);
  45   ASSERT (y < 1.628947573);
  46   y = nextafter (y, 0);
  47   ASSERT (y == x);
  48   /* Towards itself.  */
  49   y = nextafter (x, x);
  50   ASSERT (y == x);
  51
  52   return test_exit_status;
  53 }