contrib/gmp/invalid.c

   1 /* __gmp_invalid_operation -- invalid floating point operation.
   2
   3    THE FUNCTIONS IN THIS FILE ARE FOR INTERNAL USE ONLY.  THEY'RE ALMOST
   4    CERTAIN TO BE SUBJECT TO INCOMPATIBLE CHANGES OR DISAPPEAR COMPLETELY IN
   5    FUTURE GNU MP RELEASES.
   6
   7 Copyright 2003 Free Software Foundation, Inc.
   8
   9 This file is part of the GNU MP Library.
  10
  11 The GNU MP Library is free software; you can redistribute it and/or modify
  12 it under the terms of the GNU Lesser General Public License as published by
  13 the Free Software Foundation; either version 3 of the License, or (at your
  14 option) any later version.
  15
  16 The GNU MP Library is distributed in the hope that it will be useful, but
  17 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  18 or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
  19 License for more details.
  20
  21 You should have received a copy of the GNU Lesser General Public License
  22 along with the GNU MP Library.  If not, see http://www.gnu.org/licenses/.  */
  23
  24 #include "config.h"
  25
  26 #include <signal.h>
  27 #include <stdlib.h>
  28
  29 #if HAVE_UNISTD_H
  30 #include <unistd.h>  /* for getpid */
  31 #endif
  32
  33 #include "gmp.h"
  34 #include "gmp-impl.h"
  35
  36
  37 /* Incidentally, kill is not available on mingw, but that's ok, it has raise
  38    and we'll be using that.  */
  39 #if ! HAVE_RAISE
  40 #define raise(sig)   kill (getpid(), sig)
  41 #endif
  42
  43
  44 /* __gmp_invalid_operation is for an invalid floating point operation, like
  45    mpz_set_d on a NaN or Inf.  It's done as a subroutine to minimize code in
  46    places raising an exception.
  47
  48    feraiseexcept(FE_INVALID) is not used here, since unfortunately on most
  49    systems it would require libm.
  50
  51    Alternatives:
  52
  53    It might be possible to check whether a hardware "invalid operation" trap
  54    is enabled or not before raising a signal.  This would require all
  55    callers to be prepared to continue with some bogus result.  Bogus returns
  56    are bad, but presumably an application disabling the trap is prepared for
  57    that.
  58
  59    On some systems (eg. BSD) the signal handler can find out the reason for
  60    a SIGFPE (overflow, invalid, div-by-zero, etc).  Perhaps we could get
  61    that into our raise too.
  62
  63    i386 GLIBC implements feraiseexcept(FE_INVALID) with an asm fdiv 0/0.
  64    That would both respect the exceptions mask and give a reason code in a
  65    BSD signal.  */
  66
  67 void
  68 __gmp_invalid_operation (void)
  69 {
  70   raise (SIGFPE);
  71   abort ();
  72 }