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/* rwlock type. Generic version.
Copyright (C) 2002, 2005 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 Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#ifndef _BITS_RWLOCK_H
#define _BITS_RWLOCK_H
#include <bits/spin-lock.h>
/* User visible part of a rwlock. If __held is not held and readers
is 0, then the lock is unlocked. If __held is held and readers is
0, then the lock is held by a writer. If __held is held and
readers is greater than 0, then the lock is held by READERS
readers. */
struct __pthread_rwlock
{
__pthread_spinlock_t __held;
__pthread_spinlock_t __lock;
int readers;
struct __pthread *readerqueue;
struct __pthread *writerqueue;
struct __pthread_rwlockattr *__attr;
void *__data;
};
/* Initializer for a rwlock. */
#define __PTHREAD_RWLOCK_INITIALIZER \
{ __SPIN_LOCK_INITIALIZER, __SPIN_LOCK_INITIALIZER, 0, 0, 0, 0, 0 }
#if defined __USE_UNIX98 || defined __USE_XOPEN2K
_EXTERN_INLINE int
pthread_rwlock_init (struct __pthread_rwlock *__restrict __rwlock,
const struct __pthread_rwlockattr *__restrict __attr)
{
struct __pthread_rwlock initialized_rwlock = __PTHREAD_RWLOCK_INITIALIZER;
extern int _pthread_rwlock_init (struct __pthread_rwlock *,
const struct __pthread_rwlockattr *);
if (__attr)
return _pthread_rwlock_init (__rwlock, __attr);
*__rwlock = initialized_rwlock;
return 0;
}
_EXTERN_INLINE int
pthread_rwlock_destroy (struct __pthread_rwlock *__rwlock)
{
extern int _pthread_rwlock_destroy (struct __pthread_rwlock *);
if (__rwlock->__attr
|| __rwlock->__data)
return _pthread_rwlock_destroy (__rwlock);
return 0;
}
#endif
#endif /* bits/rwlock.h */
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