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042e1521c7
This commit fixes semaphore destruction by either using 64b atomic operations (where available), or by using two separate fields when only 32b atomic operations are available. In the latter case, we keep a conservative estimate of whether there are any waiting threads in one bit of the field that counts the number of available tokens, thus allowing sem_post to atomically both add a token and determine whether it needs to call futex_wake. See: https://sourceware.org/ml/libc-alpha/2014-12/msg00155.html
38 lines
1.3 KiB
C
38 lines
1.3 KiB
C
/* sem_timedwait -- wait on a semaphore with timeout.
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Copyright (C) 2003-2015 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 Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include "sem_waitcommon.c"
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/* This is in a separate file because because sem_timedwait is only provided
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if __USE_XOPEN2K is defined. */
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int
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sem_timedwait (sem_t *sem, const struct timespec *abstime)
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{
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if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)
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{
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__set_errno (EINVAL);
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return -1;
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}
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if (__new_sem_wait_fast ((struct new_sem *) sem, 0) == 0)
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return 0;
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else
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return __new_sem_wait_slow((struct new_sem *) sem, abstime);
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}
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