| /* |
| * Copyright (c) International Business Machines Corp., 2001-2004 |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program 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 General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| #ifndef _RWLOCK_H |
| #define _RWLOCK_H |
| |
| #include <pthread.h> |
| |
| /* #define RWDEBUG 1 */ |
| |
| /* n_readers >= 0 means 0 or more readers */ |
| /* n_readers < 0 means a writer */ |
| struct rwlock { |
| pthread_mutex_t plock; |
| int n_readers; |
| pthread_cond_t pcond; |
| #ifdef RWDEBUG |
| int writer_tid; |
| int n_read_waiting; |
| int n_write_waiting; |
| #endif |
| }; |
| |
| void init_rwlock(struct rwlock *rw); |
| |
| void rw_lock_read(struct rwlock *rw); |
| void rw_lock_write(struct rwlock *rw); |
| |
| void rw_unlock_read(struct rwlock *rw); |
| void rw_unlock_write(struct rwlock *rw); |
| |
| int rw_trylock_read(struct rwlock *rw); |
| int rw_trylock_write(struct rwlock *rw); |
| |
| |
| |
| #endif |