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The C and C++ Include Header Files

cat -n /usr/include/x86_64-linux-gnu/bits/stdlib.h

     1	/* Checking macros for stdlib functions.
     2	   Copyright (C) 2005-2026 Free Software Foundation, Inc.
     3	   This file is part of the GNU C Library.
     4	
     5	   The GNU C Library is free software; you can redistribute it and/or
     6	   modify it under the terms of the GNU Lesser General Public
     7	   License as published by the Free Software Foundation; either
     8	   version 2.1 of the License, or (at your option) any later version.
     9	
    10	   The GNU C Library is distributed in the hope that it will be useful,
    11	   but WITHOUT ANY WARRANTY; without even the implied warranty of
    12	   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    13	   Lesser General Public License for more details.
    14	
    15	   You should have received a copy of the GNU Lesser General Public
    16	   License along with the GNU C Library; if not, see
    17	   <https://www.gnu.org/licenses/>.  */
    18	
    19	#ifndef _STDLIB_H
    20	# error "Never include <bits/stdlib.h> directly; use <stdlib.h> instead."
    21	#endif
    22	
    23	extern char *__realpath_chk (const char *__restrict __name,
    24				     char *__restrict __resolved,
    25				     size_t __resolvedlen) __THROW __wur;
    26	extern char *__REDIRECT_NTH (__realpath_alias,
    27				     (const char *__restrict __name,
    28				      char *__restrict __resolved), realpath) __wur;
    29	extern char *__REDIRECT_NTH (__realpath_chk_warn,
    30				     (const char *__restrict __name,
    31				      char *__restrict __resolved,
    32				      size_t __resolvedlen), __realpath_chk) __wur
    33	     __warnattr ("second argument of realpath must be either NULL or at "
    34			 "least PATH_MAX bytes long buffer");
    35	
    36	__fortify_function __attribute_overloadable__ __wur char *
    37	__NTH (realpath (const char *__restrict __name,
    38			 __fortify_clang_overload_arg (char *, __restrict, __resolved)))
    39	#if defined _LIBC_LIMITS_H_ && defined PATH_MAX
    40	     __fortify_clang_warning_only_if_bos_lt (PATH_MAX, __resolved,
    41						     "second argument of realpath must be "
    42						     "either NULL or at least PATH_MAX "
    43						     "bytes long buffer")
    44	#endif
    45	{
    46	  size_t __sz = __glibc_objsize (__resolved);
    47	
    48	  if (__sz == (size_t) -1)
    49	    return __realpath_alias (__name, __resolved);
    50	
    51	#if !__fortify_use_clang && defined _LIBC_LIMITS_H_ && defined PATH_MAX
    52	  if (__glibc_unsafe_len (PATH_MAX, sizeof (char), __sz))
    53	    return __realpath_chk_warn (__name, __resolved, __sz);
    54	#endif
    55	  return __realpath_chk (__name, __resolved, __sz);
    56	}
    57	
    58	
    59	extern int __ptsname_r_chk (int __fd, char *__buf, size_t __buflen,
    60				    size_t __nreal) __THROW __nonnull ((2))
    61	    __attr_access ((__write_only__, 2, 3));
    62	extern int __REDIRECT_NTH (__ptsname_r_alias, (int __fd, char *__buf,
    63						       size_t __buflen), ptsname_r)
    64	     __nonnull ((2)) __attr_access ((__write_only__, 2, 3));
    65	extern int __REDIRECT_NTH (__ptsname_r_chk_warn,
    66				   (int __fd, char *__buf, size_t __buflen,
    67				    size_t __nreal), __ptsname_r_chk)
    68	     __nonnull ((2)) __warnattr ("ptsname_r called with buflen bigger than "
    69					 "size of buf");
    70	
    71	__fortify_function __attribute_overloadable__ int
    72	__NTH (ptsname_r (int __fd,
    73			 __fortify_clang_overload_arg (char *, ,__buf),
    74			 size_t __buflen))
    75	     __fortify_clang_warning_only_if_bos_lt (__buflen, __buf,
    76						     "ptsname_r called with buflen "
    77						     "bigger than size of buf")
    78	{
    79	  return __glibc_fortify (ptsname_r, __buflen, sizeof (char),
    80				  __glibc_objsize (__buf),
    81				  __fd, __buf, __buflen);
    82	}
    83	
    84	
    85	extern int __wctomb_chk (char *__s, wchar_t __wchar, size_t __buflen)
    86	  __THROW __wur;
    87	extern int __REDIRECT_NTH (__wctomb_alias, (char *__s, wchar_t __wchar),
    88				   wctomb) __wur;
    89	
    90	__fortify_function __attribute_overloadable__ __wur int
    91	__NTH (wctomb (__fortify_clang_overload_arg (char *, ,__s), wchar_t __wchar))
    92	{
    93	  /* We would have to include <limits.h> to get a definition of MB_LEN_MAX.
    94	     But this would only disturb the namespace.  So we define our own
    95	     version here.  */
    96	#define __STDLIB_MB_LEN_MAX	16
    97	#if defined MB_LEN_MAX && MB_LEN_MAX != __STDLIB_MB_LEN_MAX
    98	# error "Assumed value of MB_LEN_MAX wrong"
    99	#endif
   100	  if (__glibc_objsize (__s) != (size_t) -1
   101	      && __STDLIB_MB_LEN_MAX > __glibc_objsize (__s))
   102	    return __wctomb_chk (__s, __wchar, __glibc_objsize (__s));
   103	  return __wctomb_alias (__s, __wchar);
   104	}
   105	
   106	
   107	extern size_t __mbstowcs_chk (wchar_t *__restrict __dst,
   108				      const char *__restrict __src,
   109				      size_t __len, size_t __dstlen) __THROW
   110	    __attr_access ((__write_only__, 1, 3)) __attr_access ((__read_only__, 2));
   111	extern size_t __REDIRECT_NTH (__mbstowcs_nulldst,
   112				      (wchar_t *__restrict __dst,
   113				       const char *__restrict __src,
   114				       size_t __len), mbstowcs)
   115	    __attr_access ((__read_only__, 2));
   116	extern size_t __REDIRECT_NTH (__mbstowcs_alias,
   117				      (wchar_t *__restrict __dst,
   118				       const char *__restrict __src,
   119				       size_t __len), mbstowcs)
   120	    __attr_access ((__write_only__, 1, 3)) __attr_access ((__read_only__, 2));
   121	extern size_t __REDIRECT_NTH (__mbstowcs_chk_warn,
   122				      (wchar_t *__restrict __dst,
   123				       const char *__restrict __src,
   124				       size_t __len, size_t __dstlen), __mbstowcs_chk)
   125	     __warnattr ("mbstowcs called with dst buffer smaller than len "
   126			 "* sizeof (wchar_t)");
   127	
   128	__fortify_function __attribute_overloadable__ size_t
   129	__NTH (mbstowcs (__fortify_clang_overload_arg (wchar_t *, __restrict, __dst),
   130			 const char *__restrict __src,
   131			 size_t __len))
   132	     __fortify_clang_warning_only_if_bos0_lt2 (__len, __dst, sizeof (wchar_t),
   133						       "mbstowcs called with dst buffer "
   134						       "smaller than len * sizeof (wchar_t)")
   135	{
   136	  if (__builtin_constant_p (__dst == NULL) && __dst == NULL)
   137	    return __mbstowcs_nulldst (__dst, __src, __len);
   138	  else
   139	    return __glibc_fortify_n (mbstowcs, __len, sizeof (wchar_t),
   140				      __glibc_objsize (__dst), __dst, __src, __len);
   141	}
   142	
   143	extern size_t __wcstombs_chk (char *__restrict __dst,
   144				      const wchar_t *__restrict __src,
   145				      size_t __len, size_t __dstlen) __THROW
   146	  __attr_access ((__write_only__, 1, 3)) __attr_access ((__read_only__, 2));
   147	extern size_t __REDIRECT_NTH (__wcstombs_alias,
   148				      (char *__restrict __dst,
   149				       const wchar_t *__restrict __src,
   150				       size_t __len), wcstombs)
   151	  __attr_access ((__write_only__, 1, 3)) __attr_access ((__read_only__, 2));
   152	extern size_t __REDIRECT_NTH (__wcstombs_chk_warn,
   153				      (char *__restrict __dst,
   154				       const wchar_t *__restrict __src,
   155				       size_t __len, size_t __dstlen), __wcstombs_chk)
   156	     __warnattr ("wcstombs called with dst buffer smaller than len");
   157	
   158	__fortify_function __attribute_overloadable__ size_t
   159	__NTH (wcstombs (__fortify_clang_overload_arg (char *, __restrict, __dst),
   160			 const wchar_t *__restrict __src,
   161			 size_t __len))
   162	{
   163	  return __glibc_fortify (wcstombs, __len, sizeof (char),
   164				  __glibc_objsize (__dst),
   165				  __dst, __src, __len);
   166	}