math/fenv.h

   1 /* Copyright (C) 1997 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    License, or (at your option) any later version.
   8
   9    The GNU C Library 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 GNU
  12    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 /*
  20  * ISO C 9X 7.6: Floating-point environment     <fenv.h>
  21  */
  22
  23 #ifndef _FENV_H
  24
  25 #define _FENV_H 1
  26 #include <features.h>
  27
  28 /* Get the architecture dependend definitions.  The following definitions
  29    are expected to be done:
  30
  31    fenv_t       type for object representing an entire floating-point
  32                 environment
  33
  34    FE_DFL_ENV   macro of type pointer to fenv_t to be used as the argument
  35                 to functions taking an argument of type fenv_t; in this
  36                 case the default environment will be used
  37
  38    fexcept_t    type for object representing the floating-point exception
  39                 flags including status associated with the flags
  40
  41    The following macros are defined iff the implementation supports this
  42    kind of exception.
  43    FE_INEXACT           inexact result
  44    FE_DIVBYZERO         devision by zero
  45    FE_UNDERFLOW         result not representable due to underflow
  46    FE_OVERFLOW          result not representable due to overflow
  47    FE_INVALID           invalid operation
  48
  49    FE_ALL_EXCEPT        bitwise OR of all supported exceptions
  50
  51    The next macros are defined iff the appropriate rounding mode is
  52    supported by the implementation.
  53    FE_TONEAREST         round to nearest
  54    FE_UPWARD            round toward +Inf
  55    FE_DOWNWARD          round toward -Inf
  56    FE_TOWARDZERO        round toward 0
  57 */
  58 #include <fenvbits.h>
  59
  60 __BEGIN_DECLS
  61
  62 /* Floating-point exception handling.  */
  63
  64 /* Clear the supported exceptions represented by EXCEPTS.  */
  65 extern void feclearexcept __P ((int __excepts));
  66
  67 /* Store implementation-defined representation of the exception flags
  68    indicated by EXCEPTS in the object pointed to by FLAGP.  */
  69 extern void fegetexceptflag __P ((fexcept_t *__flagp, int __excepts));
  70
  71 /* Raise the supported exceptions represented by EXCEPTS.  */
  72 extern void feraiseexcept __P ((int __excepts));
  73
  74 /* Set complete status for exceptions indicated by EXCEPTS according to
  75    the representation in the object pointed to by FLAGP.  */
  76 extern void fesetexceptflag __P ((__const fexcept_t *__flagp, int __excepts));
  77
  78 /* Determine which of subset of the exceptions specified by EXCEPTS are
  79    currently set.  */
  80 extern int fetestexcept __P ((int __excepts));
  81
  82
  83 /* Rounding control.  */
  84
  85 /* Get current rounding direction.  */
  86 extern int fegetround __P ((void));
  87
  88 /* Establish the rounding direction represented by ROUND.  */
  89 extern int fesetround __P ((int __rounding_direction));
  90
  91
  92 /* Floating-point environment.  */
  93
  94 /* Store the current floating-point environment in the object pointed
  95    to by ENVP.  */
  96 extern void fegetenv __P ((fenv_t *__envp));
  97
  98 /* Save the current environment in the object pointed to by ENVP, clear
  99    exception flags and install a non-stop mode (if available) for all
 100    exceptions.  */
 101 extern int feholdexcept __P ((fenv_t *__envp));
 102
 103 /* Establish the floating-point environment represented by the object
 104    pointed to by ENVP.  */
 105 extern void fesetenv __P ((__const fenv_t *__envp));
 106
 107 /* Save current exceptions in temporary storage, install environment
 108    represented by object pointed to by ENVP and raise exceptions
 109    according to saved exceptions.  */
 110 extern void feupdateenv __P ((__const fenv_t *__envp));
 111
 112 __END_DECLS
 113
 114 #endif /* fenv.h */