math/fenv.h

   1 /* Copyright (C) 1997-2021 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 Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the 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    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 /*
  19  * ISO C99 7.6: Floating-point environment      <fenv.h>
  20  */
  21
  22 #ifndef _FENV_H
  23 #define _FENV_H 1
  24
  25 #define __GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION
  26 #include <bits/libc-header-start.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    femode_t     type for object representing floating-point control modes
  42
  43    FE_DFL_MODE  macro of type pointer to const femode_t to be used as the
  44                 argument to fesetmode; in this case the default control
  45                 modes will be used
  46
  47    The following macros are defined iff the implementation supports this
  48    kind of exception.
  49    FE_INEXACT           inexact result
  50    FE_DIVBYZERO         division by zero
  51    FE_UNDERFLOW         result not representable due to underflow
  52    FE_OVERFLOW          result not representable due to overflow
  53    FE_INVALID           invalid operation
  54
  55    FE_ALL_EXCEPT        bitwise OR of all supported exceptions
  56
  57    The next macros are defined iff the appropriate rounding mode is
  58    supported by the implementation.
  59    FE_TONEAREST         round to nearest
  60    FE_UPWARD            round toward +Inf
  61    FE_DOWNWARD          round toward -Inf
  62    FE_TOWARDZERO        round toward 0
  63 */
  64 #include <bits/fenv.h>
  65
  66 __BEGIN_DECLS
  67
  68 /* Floating-point exception handling.  */
  69
  70 /* Clear the supported exceptions represented by EXCEPTS.  */
  71 extern int feclearexcept (int __excepts) __THROW;
  72
  73 /* Store implementation-defined representation of the exception flags
  74    indicated by EXCEPTS in the object pointed to by FLAGP.  */
  75 extern int fegetexceptflag (fexcept_t *__flagp, int __excepts) __THROW;
  76
  77 /* Raise the supported exceptions represented by EXCEPTS.  */
  78 extern int feraiseexcept (int __excepts) __THROW;
  79
  80 #if __GLIBC_USE (IEC_60559_BFP_EXT_C2X)
  81 /* Set the supported exception flags represented by EXCEPTS, without
  82    causing enabled traps to be taken.  */
  83 extern int fesetexcept (int __excepts) __THROW;
  84 #endif
  85
  86 /* Set complete status for exceptions indicated by EXCEPTS according to
  87    the representation in the object pointed to by FLAGP.  */
  88 extern int fesetexceptflag (const fexcept_t *__flagp, int __excepts) __THROW;
  89
  90 /* Determine which of subset of the exceptions specified by EXCEPTS are
  91    currently set.  */
  92 extern int fetestexcept (int __excepts) __THROW;
  93
  94 #if __GLIBC_USE (IEC_60559_BFP_EXT_C2X)
  95 /* Determine which of subset of the exceptions specified by EXCEPTS
  96    are set in *FLAGP.  */
  97 extern int fetestexceptflag (const fexcept_t *__flagp, int __excepts) __THROW;
  98 #endif
  99
 100
 101 /* Rounding control.  */
 102
 103 /* Get current rounding direction.  */
 104 extern int fegetround (void) __THROW __attribute_pure__;
 105
 106 /* Establish the rounding direction represented by ROUND.  */
 107 extern int fesetround (int __rounding_direction) __THROW;
 108
 109
 110 /* Floating-point environment.  */
 111
 112 /* Store the current floating-point environment in the object pointed
 113    to by ENVP.  */
 114 extern int fegetenv (fenv_t *__envp) __THROW;
 115
 116 /* Save the current environment in the object pointed to by ENVP, clear
 117    exception flags and install a non-stop mode (if available) for all
 118    exceptions.  */
 119 extern int feholdexcept (fenv_t *__envp) __THROW;
 120
 121 /* Establish the floating-point environment represented by the object
 122    pointed to by ENVP.  */
 123 extern int fesetenv (const fenv_t *__envp) __THROW;
 124
 125 /* Save current exceptions in temporary storage, install environment
 126    represented by object pointed to by ENVP and raise exceptions
 127    according to saved exceptions.  */
 128 extern int feupdateenv (const fenv_t *__envp) __THROW;
 129
 130
 131 /* Control modes.  */
 132
 133 #if __GLIBC_USE (IEC_60559_BFP_EXT_C2X)
 134 /* Store the current floating-point control modes in the object
 135    pointed to by MODEP.  */
 136 extern int fegetmode (femode_t *__modep) __THROW;
 137
 138 /* Establish the floating-point control modes represented by the
 139    object pointed to by MODEP.  */
 140 extern int fesetmode (const femode_t *__modep) __THROW;
 141 #endif
 142
 143
 144 /* NaN support.  */
 145
 146 #if (__GLIBC_USE (IEC_60559_BFP_EXT_C2X)                \
 147      && defined FE_INVALID                      \
 148      && defined __SUPPORT_SNAN__)
 149 # define FE_SNANS_ALWAYS_SIGNAL 1
 150 #endif
 151
 152 #ifdef __USE_GNU
 153
 154 /* Enable individual exceptions.  Will not enable more exceptions than
 155    EXCEPTS specifies.  Returns the previous enabled exceptions if all
 156    exceptions are successfully set, otherwise returns -1.  */
 157 extern int feenableexcept (int __excepts) __THROW;
 158
 159 /* Disable individual exceptions.  Will not disable more exceptions than
 160    EXCEPTS specifies.  Returns the previous enabled exceptions if all
 161    exceptions are successfully disabled, otherwise returns -1.  */
 162 extern int fedisableexcept (int __excepts) __THROW;
 163
 164 /* Return enabled exceptions.  */
 165 extern int fegetexcept (void) __THROW;
 166 #endif
 167
 168 __END_DECLS
 169
 170 #endif /* fenv.h */