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/* Default read-write lock implementation struct definitions.
Copyright (C) 2019-2023 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#ifndef __RWLOCK_INTERNAL_H
#define __RWLOCK_INTERNAL_H
#include <bits/endian.h>
/* Generic struct for both POSIX read-write lock. New ports are expected
to use the default layout, however archictetures can redefine it to add
arch-specific extensions (such as lock-elision). The struct have a size
of 32 bytes on both LP32 and LP64 architectures. */
struct __pthread_rwlock_arch_t
{
unsigned int __readers;
unsigned int __writers;
unsigned int __wrphase_futex;
unsigned int __writers_futex;
unsigned int __pad3;
unsigned int __pad4;
/* FLAGS must stay at its position in the structure to maintain
binary compatibility. */
#if __BYTE_ORDER == __BIG_ENDIAN
unsigned char __pad1;
unsigned char __pad2;
unsigned char __shared;
unsigned char __flags;
#else
unsigned char __flags;
unsigned char __shared;
unsigned char __pad1;
unsigned char __pad2;
#endif
int __cur_writer;
};
#if __BYTE_ORDER == __BIG_ENDIAN
# define __PTHREAD_RWLOCK_INITIALIZER(__flags) \
0, 0, 0, 0, 0, 0, 0, 0, 0, __flags, 0
#else
# define __PTHREAD_RWLOCK_INITIALIZER(__flags) \
0, 0, 0, 0, 0, 0, __flags, 0, 0, 0, 0
#endif
#endif
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