41 lines
1.4 KiB
C++
41 lines
1.4 KiB
C++
/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2013.
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This file is part of Sortix libpthread.
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Sortix libpthread is free software: you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by the
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Free Software Foundation, either version 3 of the License, or (at your
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option) any later version.
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Sortix libpthread is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with Sortix libpthread. If not, see <http://www.gnu.org/licenses/>.
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pthread_rwlock_tryrdlock.c++
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Attempts to acquire read access to a read-write lock.
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*******************************************************************************/
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#include <errno.h>
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#include <pthread.h>
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extern "C" int pthread_rwlock_tryrdlock(pthread_rwlock_t* rwlock)
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{
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if ( int ret = pthread_mutex_trylock(&rwlock->request_mutex) )
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return errno = ret;
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while ( rwlock->num_writers || rwlock->pending_writers )
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{
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pthread_mutex_unlock(&rwlock->request_mutex);
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return errno = EBUSY;
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}
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rwlock->num_readers++;
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pthread_mutex_unlock(&rwlock->request_mutex);
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return 0;
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}
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