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The C and C++ Include Header Files

cat -n /usr/include/c++/15/stdckdint.h

     1	// C compatibility header <stdckdint.h> -*- C++ -*-
     2	
     3	// Copyright The GNU Toolchain Authors.
     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 include/stdckdint.h
    26	 *  This is a Standard C++ Library header.
    27	 */
    28	
    29	#ifndef _GLIBCXX_STDCKDINT_H
    30	#define _GLIBCXX_STDCKDINT_H
    31	
    32	#if __cplusplus > 202302L
    33	#include <type_traits>
    34	#include <concepts>
    35	
    36	#define __STDC_VERSION_STDCKDINT_H__ 202311L
    37	
    38	#ifndef _GLIBCXX_DOXYGEN
    39	// We define these in our own namespace, but let Doxygen think otherwise.
    40	namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
    41	{
    42	#endif
    43	/// @cond undocumented
    44	namespace __detail
    45	{
    46	  template<typename _Tp>
    47	    concept __cv_unqual_signed_or_unsigned_integer_type
    48	      = std::same_as<_Tp, std::remove_cv_t<_Tp>>
    49		  && std::__is_standard_integer<_Tp>::value;
    50	}
    51	/// @endcond
    52	
    53	/** Checked integer arithmetic
    54	 *
    55	 * Performs arithmetic on `__a` and `__b` and stores the result in `*__result`,
    56	 * with overflow detection.
    57	 * The arithmetic is performed in infinite signed precision, without overflow,
    58	 * then converted to the result type, `_Tp1`. If the converted result is not
    59	 * equal to the infinite precision result, the stored result is wrapped to the
    60	 * width of `_Tp1` and `true` is returned. Otherwise, the stored result is
    61	 * correct and `false` is returned.
    62	 *
    63	 * @param __result A pointer to a signed or unsigned integer type.
    64	 * @param __a      A signed or unsigned integer type.
    65	 * @param __b      A signed or unsigned integer type.
    66	 * @return True if overflow occurred, false otherwise.
    67	 * @since C++26
    68	 * @{
    69	 */
    70	template<typename _Tp1, typename _Tp2, typename _Tp3>
    71	  inline bool
    72	  ckd_add(_Tp1* __result, _Tp2 __a, _Tp3 __b)
    73	  {
    74	    using __gnu_cxx::__detail::__cv_unqual_signed_or_unsigned_integer_type;
    75	    static_assert(__cv_unqual_signed_or_unsigned_integer_type<_Tp1>);
    76	    static_assert(__cv_unqual_signed_or_unsigned_integer_type<_Tp2>);
    77	    static_assert(__cv_unqual_signed_or_unsigned_integer_type<_Tp3>);
    78	    return __builtin_add_overflow(__a, __b, __result);
    79	  }
    80	
    81	template<typename _Tp1, typename _Tp2, typename _Tp3>
    82	  inline bool
    83	  ckd_sub(_Tp1* __result, _Tp2 __a, _Tp3 __b)
    84	  {
    85	    using __gnu_cxx::__detail::__cv_unqual_signed_or_unsigned_integer_type;
    86	    static_assert(__cv_unqual_signed_or_unsigned_integer_type<_Tp1>);
    87	    static_assert(__cv_unqual_signed_or_unsigned_integer_type<_Tp2>);
    88	    static_assert(__cv_unqual_signed_or_unsigned_integer_type<_Tp3>);
    89	    return __builtin_sub_overflow(__a, __b, __result);
    90	  }
    91	
    92	template<typename _Tp1, typename _Tp2, typename _Tp3>
    93	  inline bool
    94	  ckd_mul(_Tp1* __result, _Tp2 __a, _Tp3 __b)
    95	  {
    96	    using __gnu_cxx::__detail::__cv_unqual_signed_or_unsigned_integer_type;
    97	    static_assert(__cv_unqual_signed_or_unsigned_integer_type<_Tp1>);
    98	    static_assert(__cv_unqual_signed_or_unsigned_integer_type<_Tp2>);
    99	    static_assert(__cv_unqual_signed_or_unsigned_integer_type<_Tp3>);
   100	    return __builtin_mul_overflow(__a, __b, __result);
   101	  }
   102	/// @}
   103	#ifndef _GLIBCXX_DOXYGEN
   104	}
   105	
   106	using __gnu_cxx::ckd_add;
   107	using __gnu_cxx::ckd_sub;
   108	using __gnu_cxx::ckd_mul;
   109	#endif
   110	
   111	#endif // C++26
   112	
   113	#endif // _GLIBCXX_STDCKDINT_H