/* * pthread_rwlock_check_need_init.c * * Description: * This translation unit implements read/write lock primitives. * * -------------------------------------------------------------------------- * * Pthreads-win32 - POSIX Threads Library for Win32 * Copyright(C) 1998 John E. Bossom * Copyright(C) 1999,2012 Pthreads-win32 contributors * * Homepage1: http://sourceware.org/pthreads-win32/ * Homepage2: http://sourceforge.net/projects/pthreads4w/ * * The current list of contributors is contained * in the file CONTRIBUTORS included with the source * code distribution. The list can also be seen at the * following World Wide Web location: * http://sources.redhat.com/pthreads-win32/contributors.html * * This library 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 2 of the License, or (at your option) any later version. * * This library 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 this library in the file COPYING.LIB; * if not, write to the Free Software Foundation, Inc., * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA */ #ifdef HAVE_CONFIG_H # include <config.h> #endif #include "pthread.h" #include "implement.h" INLINE int ptw32_rwlock_check_need_init (pthread_rwlock_t * rwlock) { int result = 0; ptw32_mcs_local_node_t node; /* * The following guarded test is specifically for statically * initialised rwlocks (via PTHREAD_RWLOCK_INITIALIZER). */ ptw32_mcs_lock_acquire(&ptw32_rwlock_test_init_lock, &node); /* * We got here possibly under race * conditions. Check again inside the critical section * and only initialise if the rwlock is valid (not been destroyed). * If a static rwlock has been destroyed, the application can * re-initialise it only by calling pthread_rwlock_init() * explicitly. */ if (*rwlock == PTHREAD_RWLOCK_INITIALIZER) { result = pthread_rwlock_init (rwlock, NULL); } else if (*rwlock == NULL) { /* * The rwlock has been destroyed while we were waiting to * initialise it, so the operation that caused the * auto-initialisation should fail. */ result = EINVAL; } ptw32_mcs_lock_release(&node); return result; }