1 /* 2 * ptw32_spinlock_check_need_init.c 3 * 4 * Description: 5 * This translation unit implements spin lock primitives. 6 * 7 * -------------------------------------------------------------------------- 8 * 9 * Pthreads-win32 - POSIX Threads Library for Win32 10 * Copyright(C) 1998 John E. Bossom 11 * Copyright(C) 1999,2005 Pthreads-win32 contributors 12 * 13 * Contact Email: rpj (at) callisto.canberra.edu.au 14 * 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 20 * 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. 25 * 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. 30 * 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 35 */ 36 37 #include "pthread.h" 38 #include "implement.h" 39 40 41 INLINE int 42 ptw32_spinlock_check_need_init (pthread_spinlock_t * lock) 43 { 44 int result = 0; 45 ptw32_mcs_local_node_t node; 46 47 /* 48 * The following guarded test is specifically for statically 49 * initialised spinlocks (via PTHREAD_SPINLOCK_INITIALIZER). 50 */ 51 ptw32_mcs_lock_acquire(&ptw32_spinlock_test_init_lock, &node); 52 53 /* 54 * We got here possibly under race 55 * conditions. Check again inside the critical section 56 * and only initialise if the spinlock is valid (not been destroyed). 57 * If a static spinlock has been destroyed, the application can 58 * re-initialise it only by calling pthread_spin_init() 59 * explicitly. 60 */ 61 if (*lock == PTHREAD_SPINLOCK_INITIALIZER) 62 { 63 result = pthread_spin_init (lock, PTHREAD_PROCESS_PRIVATE); 64 } 65 else if (*lock == NULL) 66 { 67 /* 68 * The spinlock has been destroyed while we were waiting to 69 * initialise it, so the operation that caused the 70 * auto-initialisation should fail. 71 */ 72 result = EINVAL; 73 } 74 75 ptw32_mcs_lock_release(&node); 76 77 return (result); 78 } 79
