tests/test-fenv-except-tracking-5.c

   1 /* Test of tracking of floating-point exceptions.
   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 <fenv.h>
  23
  24 #include <stdio.h>
  25
  26 #include "fpe-trapping.h"
  27 #include "macros.h"
  28
  29 /* musl libc does not support floating-point exception trapping, even where
  30    the hardware supports it.  See
  31    <https://wiki.musl-libc.org/functional-differences-from-glibc.html>  */
  32 #if HAVE_FPE_TRAPPING && (!MUSL_LIBC || GNULIB_FEENABLEEXCEPT)
  33
  34 /* Check that fesetexcept() does not trigger a trap.  */
  35
  36 static volatile double a, b;
  37 static volatile long double al, bl;
  38
  39 int
  40 main ()
  41 {
  42   /* Clear FE_INVALID exceptions from past operations.  */
  43   feclearexcept (FE_INVALID);
  44
  45   /* An FE_INVALID exception shall trigger a SIGFPE signal, which by default
  46      terminates the program.  */
  47   if (sigfpe_on_invalid () < 0)
  48     {
  49       fputs ("Skipping test: trapping floating-point exceptions are not supported on this machine.\n", stderr);
  50       return 77;
  51     }
  52
  53   /* Attempt to set the FE_INVALID exception flag.  */
  54   _GL_UNUSED int rc = fesetexcept (FE_INVALID);
  55   /* On older i386 and on PowerPC, there is no way to implement
  56      fesetexcept() such that it does not trigger a trap.  fesetexcept()
  57      is expected to fail in this case.  */
  58 # if !((defined __i386 || defined _M_IX86) || defined __powerpc__)
  59   ASSERT (rc == 0);
  60 # endif
  61
  62   /* Do a harmless floating-point operation (since on some CPUs, floating-point
  63      exceptions trigger a trap only at the next floating-point operation).  */
  64   a = 1.0; b = a + a;
  65   al = 1.0L; bl = al + al;
  66
  67   return test_exit_status;
  68 }
  69
  70 #else
  71
  72 int
  73 main ()
  74 {
  75   fputs ("Skipping test: feenableexcept not available\n", stderr);
  76   return 77;
  77 }
  78
  79 #endif