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242 lines
7.6 KiB
C
242 lines
7.6 KiB
C
/* Copyright (C) 2003, 2004 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Paul Mackerras <paulus@au.ibm.com>, 2003.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Libr \ary; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#ifndef _LOWLEVELLOCK_H
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#define _LOWLEVELLOCK_H 1
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#include <time.h>
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#include <sys/param.h>
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#include <bits/pthreadtypes.h>
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#include <atomic.h>
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#ifndef __NR_futex
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# define __NR_futex 221
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#endif
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#define FUTEX_WAIT 0
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#define FUTEX_WAKE 1
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#define FUTEX_REQUEUE 3
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#define FUTEX_CMP_REQUEUE 4
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/* Initializer for compatibility lock. */
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#define LLL_MUTEX_LOCK_INITIALIZER (0)
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#define lll_futex_wait(futexp, val) \
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({ \
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INTERNAL_SYSCALL_DECL (__err); \
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long int __ret; \
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\
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__ret = INTERNAL_SYSCALL (futex, __err, 4, \
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(futexp), FUTEX_WAIT, (val), 0); \
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INTERNAL_SYSCALL_ERROR_P (__ret, __err) ? -__ret : __ret; \
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})
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#define lll_futex_timed_wait(futexp, val, timespec) \
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({ \
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INTERNAL_SYSCALL_DECL (__err); \
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long int __ret; \
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\
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__ret = INTERNAL_SYSCALL (futex, __err, 4, \
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(futexp), FUTEX_WAIT, (val), (timespec)); \
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INTERNAL_SYSCALL_ERROR_P (__ret, __err) ? -__ret : __ret; \
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})
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#define lll_futex_wake(futexp, nr) \
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({ \
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INTERNAL_SYSCALL_DECL (__err); \
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long int __ret; \
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\
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__ret = INTERNAL_SYSCALL (futex, __err, 4, \
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(futexp), FUTEX_WAKE, (nr), 0); \
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INTERNAL_SYSCALL_ERROR_P (__ret, __err) ? -__ret : __ret; \
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})
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/* Returns non-zero if error happened, zero if success. */
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#define lll_futex_requeue(futexp, nr_wake, nr_move, mutex, val) \
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({ \
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INTERNAL_SYSCALL_DECL (__err); \
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long int __ret; \
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\
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__ret = INTERNAL_SYSCALL (futex, __err, 6, \
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(futexp), FUTEX_CMP_REQUEUE, (nr_wake), \
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(nr_move), (mutex), (val)); \
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INTERNAL_SYSCALL_ERROR_P (__ret, __err); \
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})
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#ifdef UP
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# define __lll_acq_instr ""
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# define __lll_rel_instr ""
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#else
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# define __lll_acq_instr "isync"
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# define __lll_rel_instr "sync"
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#endif
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/* Set *futex to 1 if it is 0, atomically. Returns the old value */
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#define __lll_trylock(futex) \
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({ int __val; \
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__asm __volatile ("1: lwarx %0,0,%2\n" \
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" cmpwi 0,%0,0\n" \
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" bne 2f\n" \
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" stwcx. %3,0,%2\n" \
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" bne- 1b\n" \
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"2: " __lll_acq_instr \
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: "=&r" (__val), "=m" (*futex) \
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: "r" (futex), "r" (1), "m" (*futex) \
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: "cr0", "memory"); \
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__val; \
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})
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#define lll_mutex_trylock(lock) __lll_trylock (&(lock))
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/* Set *futex to 2 if it is 0, atomically. Returns the old value */
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#define __lll_cond_trylock(futex) \
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({ int __val; \
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__asm __volatile ("1: lwarx %0,0,%2\n" \
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" cmpwi 0,%0,0\n" \
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" bne 2f\n" \
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" stwcx. %3,0,%2\n" \
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" bne- 1b\n" \
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"2: " __lll_acq_instr \
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: "=&r" (__val), "=m" (*futex) \
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: "r" (futex), "r" (2), "m" (*futex) \
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: "cr0", "memory"); \
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__val; \
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})
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#define lll_mutex_cond_trylock(lock) __lll_cond_trylock (&(lock))
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extern void __lll_lock_wait (int *futex) attribute_hidden;
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#define lll_mutex_lock(lock) \
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(void) ({ \
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int *__futex = &(lock); \
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if (__builtin_expect (atomic_compare_and_exchange_val_acq (__futex, 1, 0),\
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0) != 0) \
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__lll_lock_wait (__futex); \
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})
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#define lll_mutex_cond_lock(lock) \
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(void) ({ \
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int *__futex = &(lock); \
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if (__builtin_expect (atomic_compare_and_exchange_val_acq (__futex, 2, 0),\
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0) != 0) \
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__lll_lock_wait (__futex); \
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})
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extern int __lll_timedlock_wait
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(int *futex, const struct timespec *) attribute_hidden;
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#define lll_mutex_timedlock(lock, abstime) \
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({ \
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int *__futex = &(lock); \
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int __val = 0; \
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if (__builtin_expect (atomic_compare_and_exchange_val_acq (__futex, 1, 0),\
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0) != 0) \
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__val = __lll_timedlock_wait (__futex, abstime); \
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__val; \
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})
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#define lll_mutex_unlock(lock) \
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((void) ({ \
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int *__futex = &(lock); \
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int __val = atomic_exchange_rel (__futex, 0); \
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if (__builtin_expect (__val > 1, 0)) \
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lll_futex_wake (__futex, 1); \
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}))
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#define lll_mutex_unlock_force(lock) \
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((void) ({ \
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int *__futex = &(lock); \
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*__futex = 0; \
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__asm __volatile (__lll_rel_instr ::: "memory"); \
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lll_futex_wake (__futex, 1); \
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}))
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#define lll_mutex_islocked(futex) \
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(futex != 0)
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/* Our internal lock implementation is identical to the binary-compatible
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mutex implementation. */
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/* Type for lock object. */
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typedef int lll_lock_t;
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/* Initializers for lock. */
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#define LLL_LOCK_INITIALIZER (0)
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#define LLL_LOCK_INITIALIZER_LOCKED (1)
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extern int lll_unlock_wake_cb (int *__futex) attribute_hidden;
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/* The states of a lock are:
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0 - untaken
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1 - taken by one user
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>1 - taken by more users */
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#define lll_trylock(lock) lll_mutex_trylock (lock)
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#define lll_lock(lock) lll_mutex_lock (lock)
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#define lll_unlock(lock) lll_mutex_unlock (lock)
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#define lll_islocked(lock) lll_mutex_islocked (lock)
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/* The kernel notifies a process which uses CLONE_CLEARTID via futex
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wakeup when the clone terminates. The memory location contains the
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thread ID while the clone is running and is reset to zero
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afterwards. */
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#define lll_wait_tid(tid) \
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do { \
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__typeof (tid) __tid; \
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while ((__tid = (tid)) != 0) \
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lll_futex_wait (&(tid), __tid); \
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} while (0)
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extern int __lll_timedwait_tid (int *, const struct timespec *)
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attribute_hidden;
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#define lll_timedwait_tid(tid, abstime) \
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({ \
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int __res = 0; \
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if ((tid) != 0) \
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__res = __lll_timedwait_tid (&(tid), (abstime)); \
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__res; \
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})
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/* Conditional variable handling. */
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extern void __lll_cond_wait (pthread_cond_t *cond)
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attribute_hidden;
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extern int __lll_cond_timedwait (pthread_cond_t *cond,
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const struct timespec *abstime)
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attribute_hidden;
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extern void __lll_cond_wake (pthread_cond_t *cond)
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attribute_hidden;
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extern void __lll_cond_broadcast (pthread_cond_t *cond)
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attribute_hidden;
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#define lll_cond_wait(cond) \
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__lll_cond_wait (cond)
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#define lll_cond_timedwait(cond, abstime) \
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__lll_cond_timedwait (cond, abstime)
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#define lll_cond_wake(cond) \
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__lll_cond_wake (cond)
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#define lll_cond_broadcast(cond) \
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__lll_cond_broadcast (cond)
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#endif /* lowlevellock.h */
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