64 lines
1.9 KiB
C
64 lines
1.9 KiB
C
/* Copyright (C) 2003 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Martin Schwidefsky <schwidefsky@de.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 Library; 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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#include <endian.h>
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#include <errno.h>
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#include <sysdep.h>
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#include <lowlevellock.h>
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#include <pthread.h>
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#include <pthreadP.h>
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#include <shlib-compat.h>
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int
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__pthread_cond_signal (cond)
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pthread_cond_t *cond;
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{
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/* Make sure we are alone. */
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lll_mutex_lock(cond->__data.__lock);
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/* Are there any waiters to be woken? */
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if (cond->__data.__total_seq > cond->__data.__wakeup_seq)
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{
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/* Yes. Mark one of them as woken. */
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++cond->__data.__wakeup_seq;
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/* The futex syscall operates on a 32-bit word. That is fine,
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we just use the low 32 bits of the sequence counter. */
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#if BYTE_ORDER == LITTLE_ENDIAN
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int *futex = ((int *) (&cond->__data.__wakeup_seq));
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#elif BYTE_ORDER == BIG_ENDIAN
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int *futex = ((int *) (&cond->__data.__wakeup_seq)) + 1;
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#else
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# error "No valid byte order"
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#endif
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/* Wake one. */
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lll_futex_wake (futex, 1);
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}
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/* We are done. */
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lll_mutex_unlock (cond->__data.__lock);
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return 0;
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}
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versioned_symbol (libpthread, __pthread_cond_signal, pthread_cond_signal,
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GLIBC_2_3_2);
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