math/fenv.h

   1 /* Copyright (C) 1997-2015 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    <http://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 #include <features.h>
  26
  27 /* Get the architecture dependend definitions.  The following definitions
  28    are expected to be done:
  29
  30    fenv_t       type for object representing an entire floating-point
  31                 environment
  32
  33    FE_DFL_ENV   macro of type pointer to fenv_t to be used as the argument
  34                 to functions taking an argument of type fenv_t; in this
  35                 case the default environment will be used
  36
  37    fexcept_t    type for object representing the floating-point exception
  38                 flags including status associated with the flags
  39
  40    The following macros are defined iff the implementation supports this
  41    kind of exception.
  42    FE_INEXACT           inexact result
  43    FE_DIVBYZERO         division by zero
  44    FE_UNDERFLOW         result not representable due to underflow
  45    FE_OVERFLOW          result not representable due to overflow
  46    FE_INVALID           invalid operation
  47
  48    FE_ALL_EXCEPT        bitwise OR of all supported exceptions
  49
  50    The next macros are defined iff the appropriate rounding mode is
  51    supported by the implementation.
  52    FE_TONEAREST         round to nearest
  53    FE_UPWARD            round toward +Inf
  54    FE_DOWNWARD          round toward -Inf
  55    FE_TOWARDZERO        round toward 0
  56 */
  57 #include <bits/fenv.h>
  58
  59 __BEGIN_DECLS
  60
  61 /* Floating-point exception handling.  */
  62
  63 /* Clear the supported exceptions represented by EXCEPTS.  */
  64 extern int feclearexcept (int __excepts) __THROW;
  65
  66 /* Store implementation-defined representation of the exception flags
  67    indicated by EXCEPTS in the object pointed to by FLAGP.  */
  68 extern int fegetexceptflag (fexcept_t *__flagp, int __excepts) __THROW;
  69
  70 /* Raise the supported exceptions represented by EXCEPTS.  */
  71 extern int feraiseexcept (int __excepts) __THROW;
  72
  73 /* Set complete status for exceptions indicated by EXCEPTS according to
  74    the representation in the object pointed to by FLAGP.  */
  75 extern int fesetexceptflag (const fexcept_t *__flagp, int __excepts) __THROW;
  76
  77 /* Determine which of subset of the exceptions specified by EXCEPTS are
  78    currently set.  */
  79 extern int fetestexcept (int __excepts) __THROW;
  80
  81
  82 /* Rounding control.  */
  83
  84 /* Get current rounding direction.  */
  85 extern int fegetround (void) __THROW __attribute_pure__;
  86
  87 /* Establish the rounding direction represented by ROUND.  */
  88 extern int fesetround (int __rounding_direction) __THROW;
  89
  90
  91 /* Floating-point environment.  */
  92
  93 /* Store the current floating-point environment in the object pointed
  94    to by ENVP.  */
  95 extern int fegetenv (fenv_t *__envp) __THROW;
  96
  97 /* Save the current environment in the object pointed to by ENVP, clear
  98    exception flags and install a non-stop mode (if available) for all
  99    exceptions.  */
 100 extern int feholdexcept (fenv_t *__envp) __THROW;
 101
 102 /* Establish the floating-point environment represented by the object
 103    pointed to by ENVP.  */
 104 extern int fesetenv (const fenv_t *__envp) __THROW;
 105
 106 /* Save current exceptions in temporary storage, install environment
 107    represented by object pointed to by ENVP and raise exceptions
 108    according to saved exceptions.  */
 109 extern int feupdateenv (const fenv_t *__envp) __THROW;
 110
 111
 112 /* Include optimization.  */
 113 #ifdef __OPTIMIZE__
 114 # include <bits/fenvinline.h>
 115 #endif
 116
 117 #ifdef __USE_GNU
 118
 119 /* Enable individual exceptions.  Will not enable more exceptions than
 120    EXCEPTS specifies.  Returns the previous enabled exceptions if all
 121    exceptions are successfully set, otherwise returns -1.  */
 122 extern int feenableexcept (int __excepts) __THROW;
 123
 124 /* Disable individual exceptions.  Will not disable more exceptions than
 125    EXCEPTS specifies.  Returns the previous enabled exceptions if all
 126    exceptions are successfully disabled, otherwise returns -1.  */
 127 extern int fedisableexcept (int __excepts) __THROW;
 128
 129 /* Return enabled exceptions.  */
 130 extern int fegetexcept (void) __THROW;
 131 #endif
 132
 133 __END_DECLS
 134
 135 #endif /* fenv.h */