The C and C++ Include Header Files

/usr/include/c++/11/fenv.h


$ cat -n /usr/include/c++/11/fenv.h

     1	// -*- C++ -*- compatibility header.
     2	
     3	// Copyright (C) 2007-2021 Free Software Foundation, Inc.
     4	//
     5	// This file is part of the GNU ISO C++ Library.  This library is free
     6	// software; you can redistribute it and/or modify it under the
     7	// terms of the GNU General Public License as published by the
     8	// Free Software Foundation; either version 3, or (at your option)
     9	// any later version.
    10	
    11	// This library is distributed in the hope that it will be useful,
    12	// but WITHOUT ANY WARRANTY; without even the implied warranty of
    13	// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    14	// GNU General Public License for more details.
    15	
    16	// Under Section 7 of GPL version 3, you are granted additional
    17	// permissions described in the GCC Runtime Library Exception, version
    18	// 3.1, as published by the Free Software Foundation.
    19	
    20	// You should have received a copy of the GNU General Public License and
    21	// a copy of the GCC Runtime Library Exception along with this program;
    22	// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
    23	// <http://www.gnu.org/licenses/>.
    24	
    25	/** @file fenv.h
    26	 *  This is a Standard C++ Library header.
    27	 */
    28	
    29	#ifndef _GLIBCXX_FENV_H
    30	#define _GLIBCXX_FENV_H 1
    31	
    32	#pragma GCC system_header
    33	
    34	#include <bits/c++config.h>
    35	#if _GLIBCXX_HAVE_FENV_H
    36	# include_next <fenv.h>
    37	#endif
    38	
    39	#if __cplusplus >= 201103L
    40	
    41	#if _GLIBCXX_USE_C99_FENV_TR1
    42	
    43	#undef feclearexcept
    44	#undef fegetexceptflag
    45	#undef feraiseexcept
    46	#undef fesetexceptflag
    47	#undef fetestexcept
    48	#undef fegetround
    49	#undef fesetround
    50	#undef fegetenv
    51	#undef feholdexcept
    52	#undef fesetenv
    53	#undef feupdateenv
    54	
    55	namespace std
    56	{
    57	  // types
    58	  using ::fenv_t;
    59	  using ::fexcept_t;
    60	
    61	  // functions
    62	  using ::feclearexcept;
    63	  using ::fegetexceptflag;
    64	  using ::feraiseexcept;
    65	  using ::fesetexceptflag;
    66	  using ::fetestexcept;
    67	
    68	  using ::fegetround;
    69	  using ::fesetround;
    70	
    71	  using ::fegetenv;
    72	  using ::feholdexcept;
    73	  using ::fesetenv;
    74	  using ::feupdateenv;
    75	} // namespace
    76	
    77	#endif // _GLIBCXX_USE_C99_FENV_TR1
    78	
    79	#endif // C++11
    80	
    81	#endif // _GLIBCXX_FENV_H