sortix-mirror/libpthread/pthread_rwlock_wrlock.c++

38 lines
1.4 KiB
C++

/*******************************************************************************
Copyright(C) Jonas 'Sortie' Termansen 2013.
This file is part of Sortix libpthread.
Sortix libpthread 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 3 of the License, or (at your
option) any later version.
Sortix libpthread 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 Sortix libpthread. If not, see <http://www.gnu.org/licenses/>.
pthread_rwlock_wrlock.c++
Acquires write access to a read-write lock.
*******************************************************************************/
#include <pthread.h>
extern "C" int pthread_rwlock_wrlock(pthread_rwlock_t* rwlock)
{
pthread_mutex_lock(&rwlock->request_mutex);
rwlock->pending_writers++;
while ( rwlock->num_readers || rwlock->num_writers )
pthread_cond_wait(&rwlock->writer_condition, &rwlock->request_mutex);
rwlock->pending_writers--;
rwlock->num_writers = 1;
pthread_mutex_unlock(&rwlock->request_mutex);
return 0;
}