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[glibc.git] / math / fenv.h
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1 /* Copyright (C) 1997, 1999 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
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.
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.
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. */
20 * ISO C99 7.6: Floating-point environment <fenv.h>
23 #ifndef _FENV_H
24 #define _FENV_H 1
26 #include <features.h>
28 /* Get the architecture dependend definitions. The following definitions
29 are expected to be done:
31 fenv_t type for object representing an entire floating-point
32 environment
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
38 fexcept_t type for object representing the floating-point exception
39 flags including status associated with the flags
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
49 FE_ALL_EXCEPT bitwise OR of all supported exceptions
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
58 #include <bits/fenv.h>
60 __BEGIN_DECLS
62 /* Floating-point exception handling. */
64 /* Clear the supported exceptions represented by EXCEPTS. */
65 extern int feclearexcept (int __excepts) __THROW;
67 /* Store implementation-defined representation of the exception flags
68 indicated by EXCEPTS in the object pointed to by FLAGP. */
69 extern int fegetexceptflag (fexcept_t *__flagp, int __excepts) __THROW;
71 /* Raise the supported exceptions represented by EXCEPTS. */
72 extern int feraiseexcept (int __excepts) __THROW;
74 /* Set complete status for exceptions indicated by EXCEPTS according to
75 the representation in the object pointed to by FLAGP. */
76 extern int fesetexceptflag (__const fexcept_t *__flagp, int __excepts) __THROW;
78 /* Determine which of subset of the exceptions specified by EXCEPTS are
79 currently set. */
80 extern int fetestexcept (int __excepts) __THROW;
83 /* Rounding control. */
85 /* Get current rounding direction. */
86 extern int fegetround (void) __THROW;
88 /* Establish the rounding direction represented by ROUND. */
89 extern int fesetround (int __rounding_direction) __THROW;
92 /* Floating-point environment. */
94 /* Store the current floating-point environment in the object pointed
95 to by ENVP. */
96 extern int fegetenv (fenv_t *__envp) __THROW;
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 (fenv_t *__envp) __THROW;
103 /* Establish the floating-point environment represented by the object
104 pointed to by ENVP. */
105 extern int fesetenv (__const fenv_t *__envp) __THROW;
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 int feupdateenv (__const fenv_t *__envp) __THROW;
113 /* Include optimization. */
114 #ifdef __OPTIMIZE__
115 # include <bits/fenvinline.h>
116 #endif
118 #ifdef __USE_GNU
120 /* Enable individual exceptions. Will not enable more exceptions than
121 EXCEPTS specifies. Returns the previous enabled exceptions if all
122 exceptions are successfully set, otherwise returns -1. */
123 extern int feenableexcept (int __excepts) __THROW;
125 /* Disable individual exceptions. Will not disable more exceptions than
126 EXCEPTS specifies. Returns the previous enabled exceptions if all
127 exceptions are successfully disabled, otherwise returns -1. */
128 extern int fedisableexcept (int __excepts) __THROW;
130 /* Return enabled exceptions. */
131 extern int fegetexcept (void) __THROW;
132 #endif
134 __END_DECLS
136 #endif /* fenv.h */