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The C and C++ Include Header Files

cat -n /usr/include/c++/15/cstring

     1	// -*- C++ -*- forwarding header.
     2	
     3	// Copyright (C) 1997-2025 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 cstring
    26	 *  This is a Standard C++ Library file.  You should @c \#include this file
    27	 *  in your programs, rather than any of the @a *.h implementation files.
    28	 *
    29	 *  This is the C++ version of the Standard C Library header @c string.h,
    30	 *  and its contents are (mostly) the same as that header, but are all
    31	 *  contained in the namespace @c std (except for names which are defined
    32	 *  as macros in C).
    33	 */
    34	
    35	//
    36	// ISO C++ 14882: 20.4.6  C library
    37	//
    38	
    39	#ifndef _GLIBCXX_CSTRING
    40	#define _GLIBCXX_CSTRING 1
    41	
    42	#ifdef _GLIBCXX_SYSHDR
    43	#pragma GCC system_header
    44	#endif
    45	
    46	#define __glibcxx_want_freestanding_cstring
    47	#include <bits/version.h>
    48	#include <string.h>
    49	
    50	// Get rid of those macros defined in <string.h> in lieu of real functions.
    51	#undef memchr
    52	#undef memcmp
    53	#undef memcpy
    54	#undef memmove
    55	#undef memset
    56	#undef strcat
    57	#undef strchr
    58	#undef strcmp
    59	#undef strcoll
    60	#undef strcpy
    61	#undef strcspn
    62	#undef strerror
    63	#undef strlen
    64	#undef strncat
    65	#undef strncmp
    66	#undef strncpy
    67	#undef strpbrk
    68	#undef strrchr
    69	#undef strspn
    70	#undef strstr
    71	#undef strtok
    72	#undef strxfrm
    73	
    74	extern "C++"
    75	{
    76	namespace std _GLIBCXX_VISIBILITY(default)
    77	{
    78	_GLIBCXX_BEGIN_NAMESPACE_VERSION
    79	
    80	  using ::memchr;
    81	  using ::memcmp;
    82	  using ::memcpy;
    83	  using ::memmove;
    84	  using ::memset;
    85	  using ::strcat;
    86	  using ::strcmp;
    87	  using ::strcoll;
    88	  using ::strcpy;
    89	  using ::strcspn;
    90	  using ::strerror;
    91	  using ::strlen;
    92	  using ::strncat;
    93	  using ::strncmp;
    94	  using ::strncpy;
    95	  using ::strspn;
    96	#if _GLIBCXX_HOSTED || __cplusplus <= 202302L
    97	  using ::strtok;
    98	#endif
    99	  using ::strxfrm;
   100	  using ::strchr;
   101	  using ::strpbrk;
   102	  using ::strrchr;
   103	  using ::strstr;
   104	
   105	#ifndef __CORRECT_ISO_CPP_STRING_H_PROTO
   106	  inline void*
   107	  memchr(void* __s, int __c, size_t __n)
   108	  { return __builtin_memchr(__s, __c, __n); }
   109	
   110	  inline char*
   111	  strchr(char* __s, int __n)
   112	  { return __builtin_strchr(__s, __n); }
   113	
   114	  inline char*
   115	  strpbrk(char* __s1, const char* __s2)
   116	  { return __builtin_strpbrk(__s1, __s2); }
   117	
   118	  inline char*
   119	  strrchr(char* __s, int __n)
   120	  { return __builtin_strrchr(__s, __n); }
   121	
   122	  inline char*
   123	  strstr(char* __s1, const char* __s2)
   124	  { return __builtin_strstr(__s1, __s2); }
   125	#endif
   126	
   127	_GLIBCXX_END_NAMESPACE_VERSION
   128	} // namespace
   129	} // extern "C++"
   130	
   131	#endif