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The C and C++ Include Header Files

cat -n /usr/include/strings.h

     1	/* Copyright (C) 1991-2026 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	#ifndef	_STRINGS_H
    19	#define	_STRINGS_H	1
    20	
    21	#include <features.h>
    22	#define __need_size_t
    23	#include <stddef.h>
    24	
    25	/* Tell the caller that we provide correct C++ prototypes.  */
    26	#if defined __cplusplus && __GNUC_PREREQ (4, 4)
    27	# define __CORRECT_ISO_CPP_STRINGS_H_PROTO
    28	#endif
    29	
    30	__BEGIN_DECLS
    31	
    32	#if defined __USE_MISC || !defined __USE_XOPEN2K8
    33	/* Compare N bytes of S1 and S2 (same as memcmp).  */
    34	extern int bcmp (const void *__s1, const void *__s2, size_t __n)
    35	     __THROW __attribute_pure__ __nonnull ((1, 2));
    36	
    37	/* Copy N bytes of SRC to DEST (like memmove, but args reversed).  */
    38	extern void bcopy (const void *__src, void *__dest, size_t __n)
    39	  __THROW __nonnull ((1, 2));
    40	
    41	/* Set N bytes of S to 0.  */
    42	extern void bzero (void *__s, size_t __n) __THROW __nonnull ((1));
    43	
    44	/* Find the first occurrence of C in S (same as strchr).  */
    45	# ifdef __CORRECT_ISO_CPP_STRINGS_H_PROTO
    46	extern "C++"
    47	{
    48	extern char *index (char *__s, int __c)
    49	     __THROW __asm ("index") __attribute_pure__ __nonnull ((1));
    50	extern const char *index (const char *__s, int __c)
    51	     __THROW __asm ("index") __attribute_pure__ __nonnull ((1));
    52	
    53	#  if defined __OPTIMIZE__
    54	__extern_always_inline char *
    55	index (char *__s, int __c) __THROW
    56	{
    57	  return __builtin_index (__s, __c);
    58	}
    59	
    60	__extern_always_inline const char *
    61	index (const char *__s, int __c) __THROW
    62	{
    63	  return __builtin_index (__s, __c);
    64	}
    65	#  endif
    66	}
    67	# else
    68	extern char *index (const char *__s, int __c)
    69	     __THROW __attribute_pure__ __nonnull ((1));
    70	# endif
    71	
    72	/* Find the last occurrence of C in S (same as strrchr).  */
    73	# ifdef __CORRECT_ISO_CPP_STRINGS_H_PROTO
    74	extern "C++"
    75	{
    76	extern char *rindex (char *__s, int __c)
    77	     __THROW __asm ("rindex") __attribute_pure__ __nonnull ((1));
    78	extern const char *rindex (const char *__s, int __c)
    79	     __THROW __asm ("rindex") __attribute_pure__ __nonnull ((1));
    80	
    81	#  if defined __OPTIMIZE__
    82	__extern_always_inline char *
    83	rindex (char *__s, int __c) __THROW
    84	{
    85	  return __builtin_rindex (__s, __c);
    86	}
    87	
    88	__extern_always_inline const char *
    89	rindex (const char *__s, int __c) __THROW
    90	{
    91	  return __builtin_rindex (__s, __c);
    92	}
    93	#  endif
    94	}
    95	# else
    96	extern char *rindex (const char *__s, int __c)
    97	     __THROW __attribute_pure__ __nonnull ((1));
    98	# endif
    99	#endif
   100	
   101	#if defined __USE_MISC || !defined __USE_XOPEN2K8 || defined __USE_XOPEN2K8XSI
   102	/* Return the position of the first bit set in I, or 0 if none are set.
   103	   The least-significant bit is position 1, the most-significant 32.  */
   104	extern int ffs (int __i) __THROW __attribute_const__;
   105	#endif
   106	
   107	/* The following two functions are non-standard but necessary for non-32 bit
   108	   platforms.  */
   109	# ifdef	__USE_MISC
   110	extern int ffsl (long int __l) __THROW __attribute_const__;
   111	__extension__ extern int ffsll (long long int __ll)
   112	     __THROW __attribute_const__;
   113	# endif
   114	
   115	/* Compare S1 and S2, ignoring case.  */
   116	extern int strcasecmp (const char *__s1, const char *__s2)
   117	     __THROW __attribute_pure__ __nonnull ((1, 2));
   118	
   119	/* Compare no more than N chars of S1 and S2, ignoring case.  */
   120	extern int strncasecmp (const char *__s1, const char *__s2, size_t __n)
   121	     __THROW __attribute_pure__ __nonnull ((1, 2));
   122	
   123	#ifdef	__USE_XOPEN2K8
   124	/* POSIX.1-2008 extended locale interface (see locale.h).  */
   125	# include <bits/types/locale_t.h>
   126	
   127	/* Compare S1 and S2, ignoring case, using collation rules from LOC.  */
   128	extern int strcasecmp_l (const char *__s1, const char *__s2, locale_t __loc)
   129	     __THROW __attribute_pure__ __nonnull ((1, 2, 3));
   130	
   131	/* Compare no more than N chars of S1 and S2, ignoring case, using
   132	   collation rules from LOC.  */
   133	extern int strncasecmp_l (const char *__s1, const char *__s2,
   134				  size_t __n, locale_t __loc)
   135	     __THROW __attribute_pure__ __nonnull ((1, 2, 4));
   136	#endif
   137	
   138	__END_DECLS
   139	
   140	#if __GNUC_PREREQ (3,4) && __USE_FORTIFY_LEVEL > 0 \
   141	    && defined __fortify_function
   142	/* Functions with security checks.  */
   143	# if defined __USE_MISC || !defined __USE_XOPEN2K8
   144	#  include <bits/strings_fortified.h>
   145	# endif
   146	#endif
   147	
   148	#endif	/* strings.h  */