1 /* 2 * pthread_mutexattr_settype.c 3 * 4 * Description: 5 * This translation unit implements mutual exclusion (mutex) 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_mutexattr_settype (pthread_mutexattr_t * attr, int kind) 43 /* 44 * ------------------------------------------------------ 45 * 46 * DOCPUBLIC 47 * The pthread_mutexattr_settype() and 48 * pthread_mutexattr_gettype() functions respectively set and 49 * get the mutex type attribute. This attribute is set in the 50 * type parameter to these functions. 51 * 52 * PARAMETERS 53 * attr 54 * pointer to an instance of pthread_mutexattr_t 55 * 56 * type 57 * must be one of: 58 * 59 * PTHREAD_MUTEX_DEFAULT 60 * 61 * PTHREAD_MUTEX_NORMAL 62 * 63 * PTHREAD_MUTEX_ERRORCHECK 64 * 65 * PTHREAD_MUTEX_RECURSIVE 66 * 67 * DESCRIPTION 68 * The pthread_mutexattr_settype() and 69 * pthread_mutexattr_gettype() functions respectively set and 70 * get the mutex type attribute. This attribute is set in the 71 * type parameter to these functions. The default value of the 72 * type attribute is PTHREAD_MUTEX_DEFAULT. 73 * 74 * The type of mutex is contained in the type attribute of the 75 * mutex attributes. Valid mutex types include: 76 * 77 * PTHREAD_MUTEX_NORMAL 78 * This type of mutex does not detect deadlock. A 79 * thread attempting to relock this mutex without 80 * first unlocking it will deadlock. Attempting to 81 * unlock a mutex locked by a different thread 82 * results in undefined behavior. Attempting to 83 * unlock an unlocked mutex results in undefined 84 * behavior. 85 * 86 * PTHREAD_MUTEX_ERRORCHECK 87 * This type of mutex provides error checking. A 88 * thread attempting to relock this mutex without 89 * first unlocking it will return with an error. A 90 * thread attempting to unlock a mutex which another 91 * thread has locked will return with an error. A 92 * thread attempting to unlock an unlocked mutex will 93 * return with an error. 94 * 95 * PTHREAD_MUTEX_DEFAULT 96 * Same as PTHREAD_MUTEX_NORMAL. 97 * 98 * PTHREAD_MUTEX_RECURSIVE 99 * A thread attempting to relock this mutex without 100 * first unlocking it will succeed in locking the 101 * mutex. The relocking deadlock which can occur with 102 * mutexes of type PTHREAD_MUTEX_NORMAL cannot occur 103 * with this type of mutex. Multiple locks of this 104 * mutex require the same number of unlocks to 105 * release the mutex before another thread can 106 * acquire the mutex. A thread attempting to unlock a 107 * mutex which another thread has locked will return 108 * with an error. A thread attempting to unlock an 109 * unlocked mutex will return with an error. This 110 * type of mutex is only supported for mutexes whose 111 * process shared attribute is 112 * PTHREAD_PROCESS_PRIVATE. 113 * 114 * RESULTS 115 * 0 successfully set attribute, 116 * EINVAL 'attr' or 'type' is invalid, 117 * 118 * ------------------------------------------------------ 119 */ 120 { 121 int result = 0; 122 123 if ((attr != NULL && *attr != NULL)) 124 { 125 switch (kind) 126 { 127 case PTHREAD_MUTEX_FAST_NP: 128 case PTHREAD_MUTEX_RECURSIVE_NP: 129 case PTHREAD_MUTEX_ERRORCHECK_NP: 130 (*attr)->kind = kind; 131 break; 132 default: 133 result = EINVAL; 134 break; 135 } 136 } 137 else 138 { 139 result = EINVAL; 140 } 141 142 return (result); 143 } /* pthread_mutexattr_settype */ 144
