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The C and C++ Include Header Files

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

     1	/* x86 internal mutex struct definitions.
     2	   Copyright (C) 2019-2026 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	   <http://www.gnu.org/licenses/>.  */
    18	
    19	#ifndef _THREAD_MUTEX_INTERNAL_H
    20	#define _THREAD_MUTEX_INTERNAL_H 1
    21	
    22	struct __pthread_mutex_s
    23	{
    24	  int __lock;
    25	  unsigned int __count;
    26	  int __owner;
    27	#ifdef __x86_64__
    28	  unsigned int __nusers;
    29	#endif
    30	  /* KIND must stay at this position in the structure to maintain
    31	     binary compatibility with static initializers.  */
    32	  int __kind;
    33	#ifdef __x86_64__
    34	  short __spins;
    35	  short __unused;
    36	  __pthread_list_t __list;
    37	# define __PTHREAD_MUTEX_HAVE_PREV      1
    38	#else
    39	  unsigned int __nusers;
    40	  __extension__ union
    41	  {
    42	    struct
    43	    {
    44	      short __data_spins;
    45	      short __data_unused;
    46	# define __spins __data.__data_spins
    47	    } __data;
    48	    __pthread_slist_t __list;
    49	  };
    50	# define __PTHREAD_MUTEX_HAVE_PREV      0
    51	#endif
    52	};
    53	
    54	#ifdef __x86_64__
    55	# define __PTHREAD_MUTEX_INITIALIZER(__kind) \
    56	  0, 0, 0, 0, __kind, 0, 0, { NULL, NULL }
    57	#else
    58	# define __PTHREAD_MUTEX_INITIALIZER(__kind) \
    59	  0, 0, 0, __kind, 0, { { 0, 0 } }
    60	#endif
    61	
    62	#endif