tests/test-copysign.c

   1 /* Test of copysign() function.
   2    Copyright (C) 2010-2018 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 (copysign, double, (double, double));
  25
  26 #include "macros.h"
  27 #include "minus-zero.h"
  28
  29 #include <string.h>
  30
  31 volatile double x;
  32 volatile double y;
  33 double z;
  34 double zero = 0.0;
  35
  36 int
  37 main ()
  38 {
  39   /* A particular value in the first quadrant.  */
  40   x = 0.6;
  41   y = 0.8;
  42   z = copysign (x, y);
  43   ASSERT (z == 0.6);
  44
  45   /* A particular value in the second quadrant.  */
  46   x = -0.6;
  47   y = 0.8;
  48   z = copysign (x, y);
  49   ASSERT (z == 0.6);
  50
  51   /* A particular value in the third quadrant.  */
  52   x = -0.6;
  53   y = -0.8;
  54   z = copysign (x, y);
  55   ASSERT (z == -0.6);
  56
  57   /* A particular value in the fourth quadrant.  */
  58   x = 0.6;
  59   y = -0.8;
  60   z = copysign (x, y);
  61   ASSERT (z == -0.6);
  62
  63   /* From signed zero.  */
  64   x = 1.0;
  65   y = 0.0;
  66   z = copysign (x, y);
  67   ASSERT (z == 1.0);
  68
  69   x = 1.0;
  70   y = minus_zerod;
  71   z = copysign (x, y);
  72   /* Assume all gnulib targets support -0.0, until proven otherwise.  */
  73   ASSERT (z == -1.0);
  74
  75   x = -1.0;
  76   y = 0.0;
  77   z = copysign (x, y);
  78   ASSERT (z == 1.0);
  79
  80   x = -1.0;
  81   y = minus_zerod;
  82   z = copysign (x, y);
  83   ASSERT (z == -1.0);
  84
  85   /* To signed zero.  */
  86   x = 0.0;
  87   y = 1.0;
  88   z = copysign (x, y);
  89   ASSERT (z == 0.0);
  90   ASSERT (memcmp (&z, &zero, sizeof z) == 0);
  91
  92   x = 0.0;
  93   y = -1.0;
  94   z = copysign (x, y);
  95   ASSERT (z == 0.0);
  96   ASSERT (memcmp (&z, &zero, sizeof z) != 0);
  97
  98   x = minus_zerod;
  99   y = 1.0;
 100   z = copysign (x, y);
 101   ASSERT (z == 0.0);
 102   ASSERT (memcmp (&z, &zero, sizeof z) == 0);
 103
 104   x = minus_zerod;
 105   y = -1.0;
 106   z = copysign (x, y);
 107   ASSERT (z == 0.0);
 108   ASSERT (memcmp (&z, &zero, sizeof z) != 0);
 109
 110   return 0;
 111 }