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/* Copyright (C) 2003-2015 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Martin Schwidefsky <schwidefsky@de.ibm.com>, 2003.
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/>. */
#include <endian.h>
#include <errno.h>
#include <sysdep.h>
#include <lowlevellock.h>
#include <pthread.h>
#include <pthreadP.h>
#include <shlib-compat.h>
#include <kernel-features.h>
#include <stap-probe.h>
int
__pthread_cond_signal (pthread_cond_t *cond)
{
int pshared = (cond->__data.__mutex == (void *) ~0l)
? LLL_SHARED : LLL_PRIVATE;
LIBC_PROBE (cond_signal, 1, cond);
/* Make sure we are alone. */
lll_lock (cond->__data.__lock, pshared);
/* Are there any waiters to be woken? */
if (cond->__data.__total_seq > cond->__data.__wakeup_seq)
{
/* Yes. Mark one of them as woken. */
++cond->__data.__wakeup_seq;
++cond->__data.__futex;
#if (defined lll_futex_cmp_requeue_pi \
&& defined __ASSUME_REQUEUE_PI)
pthread_mutex_t *mut = cond->__data.__mutex;
if (USE_REQUEUE_PI (mut)
/* This can only really fail with a ENOSYS, since nobody can modify
futex while we have the cond_lock. */
&& lll_futex_cmp_requeue_pi (&cond->__data.__futex, 1, 0,
&mut->__data.__lock,
cond->__data.__futex, pshared) == 0)
{
lll_unlock (cond->__data.__lock, pshared);
return 0;
}
else
#endif
/* Wake one. */
if (! __builtin_expect (lll_futex_wake_unlock (&cond->__data.__futex,
1, 1,
&cond->__data.__lock,
pshared), 0))
return 0;
/* Fallback if neither of them work. */
lll_futex_wake (&cond->__data.__futex, 1, pshared);
}
/* We are done. */
lll_unlock (cond->__data.__lock, pshared);
return 0;
}
versioned_symbol (libpthread, __pthread_cond_signal, pthread_cond_signal,
GLIBC_2_3_2);
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