2 * pthread_rwlock_check_need_init.c
5 * This translation unit implements read/write lock primitives.
7 * --------------------------------------------------------------------------
9 * Pthreads-win32 - POSIX Threads Library for Win32
10 * Copyright(C) 1998 John E. Bossom
11 * Copyright(C) 1999,2005 Pthreads-win32 contributors
13 * Contact Email: rpj@callisto.canberra.edu.au
15 * The current list of contributors is contained
16 * in the file CONTRIBUTORS included with the source
17 * code distribution. The list can also be seen at the
18 * following World Wide Web location:
19 * http://sources.redhat.com/pthreads-win32/contributors.html
21 * This library is free software; you can redistribute it and/or
22 * modify it under the terms of the GNU Lesser General Public
23 * License as published by the Free Software Foundation; either
24 * version 2 of the License, or (at your option) any later version.
26 * This library is distributed in the hope that it will be useful,
27 * but WITHOUT ANY WARRANTY; without even the implied warranty of
28 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
29 * Lesser General Public License for more details.
31 * You should have received a copy of the GNU Lesser General Public
32 * License along with this library in the file COPYING.LIB;
33 * if not, write to the Free Software Foundation, Inc.,
34 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
38 #include "implement.h"
41 ptw32_rwlock_check_need_init (pthread_rwlock_t * rwlock)
44 ptw32_mcs_local_node_t node;
47 * The following guarded test is specifically for statically
48 * initialised rwlocks (via PTHREAD_RWLOCK_INITIALIZER).
50 ptw32_mcs_lock_acquire(&ptw32_rwlock_test_init_lock, &node);
53 * We got here possibly under race
54 * conditions. Check again inside the critical section
55 * and only initialise if the rwlock is valid (not been destroyed).
56 * If a static rwlock has been destroyed, the application can
57 * re-initialise it only by calling pthread_rwlock_init()
60 if (*rwlock == PTHREAD_RWLOCK_INITIALIZER)
62 result = pthread_rwlock_init (rwlock, NULL);
64 else if (*rwlock == NULL)
67 * The rwlock has been destroyed while we were waiting to
68 * initialise it, so the operation that caused the
69 * auto-initialisation should fail.
74 ptw32_mcs_lock_release(&node);