1 /* 2 * pthread_spin_lock.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_lock (pthread_spinlock_t * lock) 43 { 44 register pthread_spinlock_t s; 45 46 if (NULL == lock || NULL == *lock) 47 { 48 return (EINVAL); 49 } 50 51 if (*lock == PTHREAD_SPINLOCK_INITIALIZER) 52 { 53 int result; 54 55 if ((result = ptw32_spinlock_check_need_init (lock)) != 0) 56 { 57 return (result); 58 } 59 } 60 61 s = *lock; 62 63 while ((PTW32_INTERLOCKED_LONG) PTW32_SPIN_LOCKED == 64 PTW32_INTERLOCKED_COMPARE_EXCHANGE_LONG ((PTW32_INTERLOCKED_LONGPTR) &s->interlock, 65 (PTW32_INTERLOCKED_LONG) PTW32_SPIN_LOCKED, 66 (PTW32_INTERLOCKED_LONG) PTW32_SPIN_UNLOCKED)) 67 { 68 } 69 70 if (s->interlock == PTW32_SPIN_LOCKED) 71 { 72 return 0; 73 } 74 else if (s->interlock == PTW32_SPIN_USE_MUTEX) 75 { 76 return pthread_mutex_lock (&(s->u.mutex)); 77 } 78 79 return EINVAL; 80 } 81
