1 /* 2 * pthread_spin_destroy.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 int 42 pthread_spin_destroy (pthread_spinlock_t * lock) 43 { 44 register pthread_spinlock_t s; 45 int result = 0; 46 47 if (lock == NULL || *lock == NULL) 48 { 49 return EINVAL; 50 } 51 52 if ((s = *lock) != PTHREAD_SPINLOCK_INITIALIZER) 53 { 54 if (s->interlock == PTW32_SPIN_USE_MUTEX) 55 { 56 result = pthread_mutex_destroy (&(s->u.mutex)); 57 } 58 else if ((PTW32_INTERLOCKED_LONG) PTW32_SPIN_UNLOCKED != 59 PTW32_INTERLOCKED_COMPARE_EXCHANGE_LONG ((PTW32_INTERLOCKED_LONGPTR) &s->interlock, 60 (PTW32_INTERLOCKED_LONG) PTW32_SPIN_INVALID, 61 (PTW32_INTERLOCKED_LONG) PTW32_SPIN_UNLOCKED)) 62 { 63 result = EINVAL; 64 } 65 66 if (0 == result) 67 { 68 /* 69 * We are relying on the application to ensure that all other threads 70 * have finished with the spinlock before destroying it. 71 */ 72 *lock = NULL; 73 (void) free (s); 74 } 75 } 76 else 77 { 78 /* 79 * See notes in ptw32_spinlock_check_need_init() above also. 80 */ 81 ptw32_mcs_local_node_t node; 82 83 ptw32_mcs_lock_acquire(&ptw32_spinlock_test_init_lock, &node); 84 85 /* 86 * Check again. 87 */ 88 if (*lock == PTHREAD_SPINLOCK_INITIALIZER) 89 { 90 /* 91 * This is all we need to do to destroy a statically 92 * initialised spinlock that has not yet been used (initialised). 93 * If we get to here, another thread 94 * waiting to initialise this mutex will get an EINVAL. 95 */ 96 *lock = NULL; 97 } 98 else 99 { 100 /* 101 * The spinlock has been initialised while we were waiting 102 * so assume it's in use. 103 */ 104 result = EBUSY; 105 } 106 107 ptw32_mcs_lock_release(&node); 108 } 109 110 return (result); 111 } 112
