tests/test-nan-2.c

   1 /* Tests of quiet not-a-number.
   2    Copyright (C) 2023-2024 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>, 2023.  */
  18
  19 #include <config.h>
  20
  21 /* Specification.  */
  22 #include "nan.h"
  23
  24 #include <stdio.h>
  25
  26 #include "fpe-trapping.h"
  27
  28 #if HAVE_FPE_TRAPPING
  29
  30 # include <fenv.h>
  31
  32 # include "macros.h"
  33
  34 float volatile resultf;
  35 double volatile resultd;
  36 long double volatile resultl;
  37
  38 int
  39 main ()
  40 {
  41   /* Fetch the NaN values before we start watching out for FE_INVALID
  42      exceptions, because the division 0.0 / 0.0 itself also raises an
  43      FE_INVALID exception.
  44      The use of 'volatile' prevents the compiler from doing constant-folding
  45      optimizations on these values.  An alternative, for GCC only, would be
  46      the command-line option '-fsignaling-nans'.  */
  47   float volatile nanf = NaNf ();
  48   double volatile nand = NaNd ();
  49   long double volatile nanl = NaNl ();
  50
  51   /* Check that the values are really quiet.  */
  52
  53   /* Clear FE_INVALID exceptions from past operations.  */
  54   feclearexcept (FE_INVALID);
  55
  56   /* An FE_INVALID exception shall trigger a SIGFPE signal, which by default
  57      terminates the program.  */
  58   if (sigfpe_on_invalid () < 0)
  59     {
  60       fputs ("Skipping test: trapping floating-point exceptions are not supported on this machine.\n", stderr);
  61       return 77;
  62     }
  63
  64   resultf = nanf + 42.0f;
  65   resultd = nand + 42.0;
  66   resultl = nanl + 42.0L;
  67
  68   return test_exit_status;
  69 }
  70
  71 #else
  72
  73 /* No HAVE_FPE_TRAPPING available.
  74    We could use the various alternative approaches from
  75    libgfortran/config/fpu-*.h, but that's not worth it.  */
  76
  77 int
  78 main ()
  79 {
  80   fputs ("Skipping test: feenableexcept not available\n", stderr);
  81   return 77;
  82 }
  83
  84 #endif