The C and C++ Include Header Files

/usr/include/fenv.h


$ cat -n /usr/include/fenv.h

     1	/* Copyright (C) 1997-2024 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.  */
    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 */