| yuezonghe | 824eb0c | 2024-06-27 02:32:26 -0700 | [diff] [blame^] | 1 | /* Copyright (C) 2002, 2007 Free Software Foundation, Inc. |
| 2 | This file is part of the GNU C Library. |
| 3 | Contributed by Ulrich Drepper <drepper@redhat.com>, 2002. |
| 4 | |
| 5 | The GNU C Library is free software; you can redistribute it and/or |
| 6 | modify it under the terms of the GNU Lesser General Public |
| 7 | License as published by the Free Software Foundation; either |
| 8 | version 2.1 of the License, or (at your option) any later version. |
| 9 | |
| 10 | The GNU C Library is distributed in the hope that it will be useful, |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 13 | Lesser General Public License for more details. |
| 14 | |
| 15 | You should have received a copy of the GNU Lesser General Public |
| 16 | License along with the GNU C Library; if not, write to the Free |
| 17 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 18 | 02111-1307 USA. */ |
| 19 | |
| 20 | #include <errno.h> |
| 21 | #include "pthreadP.h" |
| 22 | #include <lowlevellock.h> |
| 23 | |
| 24 | |
| 25 | int |
| 26 | __pthread_rwlock_tryrdlock ( |
| 27 | pthread_rwlock_t *rwlock) |
| 28 | { |
| 29 | int result = EBUSY; |
| 30 | |
| 31 | lll_lock (rwlock->__data.__lock, rwlock->__data.__shared); |
| 32 | |
| 33 | if (rwlock->__data.__writer == 0 |
| 34 | && (rwlock->__data.__nr_writers_queued == 0 |
| 35 | || PTHREAD_RWLOCK_PREFER_READER_P (rwlock))) |
| 36 | { |
| 37 | if (__builtin_expect (++rwlock->__data.__nr_readers == 0, 0)) |
| 38 | { |
| 39 | --rwlock->__data.__nr_readers; |
| 40 | result = EAGAIN; |
| 41 | } |
| 42 | else |
| 43 | result = 0; |
| 44 | } |
| 45 | |
| 46 | lll_unlock (rwlock->__data.__lock, rwlock->__data.__shared); |
| 47 | |
| 48 | return result; |
| 49 | } |
| 50 | strong_alias (__pthread_rwlock_tryrdlock, pthread_rwlock_tryrdlock) |