1 /* 2 * pthread_once.c 3 * 4 * Description: 5 * This translation unit implements miscellaneous thread functions. 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 int 41 pthread_once (pthread_once_t * once_control, void (PTW32_CDECL *init_routine) (void)) 42 { 43 if (once_control == NULL || init_routine == NULL) 44 { 45 return EINVAL; 46 } 47 48 if ((PTW32_INTERLOCKED_LONG)PTW32_FALSE == 49 (PTW32_INTERLOCKED_LONG)PTW32_INTERLOCKED_EXCHANGE_ADD_LONG((PTW32_INTERLOCKED_LONGPTR)&once_control->done, 50 (PTW32_INTERLOCKED_LONG)0)) /* MBR fence */ 51 { 52 ptw32_mcs_local_node_t node; 53 54 ptw32_mcs_lock_acquire((ptw32_mcs_lock_t *)&once_control->lock, &node); 55 56 if (!once_control->done) 57 { 58 59 #if defined(_MSC_VER) && _MSC_VER < 1400 60 #pragma inline_depth(0) 61 #endif 62 63 pthread_cleanup_push(ptw32_mcs_lock_release, &node); 64 (*init_routine)(); 65 pthread_cleanup_pop(0); 66 67 #if defined(_MSC_VER) && _MSC_VER < 1400 68 #pragma inline_depth() 69 #endif 70 71 once_control->done = PTW32_TRUE; 72 } 73 74 ptw32_mcs_lock_release(&node); 75 } 76 77 return 0; 78 79 } /* pthread_once */ 80
