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1/* Copyright (C) 1997-2025 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 dependent 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. */
71extern 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. */
75extern int fegetexceptflag (fexcept_t *__flagp, int __excepts) __THROW;
76
77/* Raise the supported exceptions represented by EXCEPTS. */
78extern int feraiseexcept (int __excepts) __THROW;
79
80#if __GLIBC_USE (IEC_60559_BFP_EXT_C23)
81/* Set the supported exception flags represented by EXCEPTS, without
82 causing enabled traps to be taken. */
83extern 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. */
88extern 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. */
92extern int fetestexcept (int __excepts) __THROW;
93
94#if __GLIBC_USE (IEC_60559_BFP_EXT_C23)
95/* Determine which of subset of the exceptions specified by EXCEPTS
96 are set in *FLAGP. */
97extern int fetestexceptflag (const fexcept_t *__flagp, int __excepts) __THROW;
98#endif
99
100
101/* Rounding control. */
102
103/* Get current rounding direction. */
104extern int fegetround (void) __THROW __attribute_pure__;
105
106/* Establish the rounding direction represented by ROUND. */
107extern 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. */
114extern 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. */
119extern int feholdexcept (fenv_t *__envp) __THROW;
120
121/* Establish the floating-point environment represented by the object
122 pointed to by ENVP. */
123extern 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. */
128extern int feupdateenv (const fenv_t *__envp) __THROW;
129
130
131/* Control modes. */
132
133#if __GLIBC_USE (IEC_60559_BFP_EXT_C23)
134/* Store the current floating-point control modes in the object
135 pointed to by MODEP. */
136extern int fegetmode (femode_t *__modep) __THROW;
137
138/* Establish the floating-point control modes represented by the
139 object pointed to by MODEP. */
140extern int fesetmode (const femode_t *__modep) __THROW;
141#endif
142
143
144/* NaN support. */
145
146#if (__GLIBC_USE (IEC_60559_BFP_EXT_C23) \
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. */
157extern 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. */
162extern int fedisableexcept (int __excepts) __THROW;
163
164/* Return enabled exceptions. */
165extern int fegetexcept (void) __THROW;
166#endif
167
168__END_DECLS
169
170#endif /* fenv.h */