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/* Basic platform-independent macro definitions for mutexes,
thread-specific data and parameters for malloc.
Copyright (C) 2003-2016 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 _GENERIC_MALLOC_MACHINE_H
#define _GENERIC_MALLOC_MACHINE_H
#include <atomic.h>
#ifndef mutex_init /* No threads, provide dummy macros */
# define NO_THREADS
/* The mutex functions used to do absolutely nothing, i.e. lock,
trylock and unlock would always just return 0. However, even
without any concurrently active threads, a mutex can be used
legitimately as an `in use' flag. To make the code that is
protected by a mutex async-signal safe, these macros would have to
be based on atomic test-and-set operations, for example. */
typedef int mutex_t;
# define mutex_init(m) (*(m) = 0)
# define mutex_lock(m) ({ *(m) = 1; 0; })
# define mutex_trylock(m) (*(m) ? 1 : ((*(m) = 1), 0))
# define mutex_unlock(m) (*(m) = 0)
#endif /* !defined mutex_init */
#ifndef atomic_full_barrier
# define atomic_full_barrier() __asm ("" ::: "memory")
#endif
#ifndef atomic_read_barrier
# define atomic_read_barrier() atomic_full_barrier ()
#endif
#ifndef atomic_write_barrier
# define atomic_write_barrier() atomic_full_barrier ()
#endif
#ifndef DEFAULT_TOP_PAD
# define DEFAULT_TOP_PAD 131072
#endif
#endif /* !defined(_GENERIC_MALLOC_MACHINE_H) */
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