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1 /* -*- mode: C; c-file-style: "gnu" -*- */ |
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2 /* dbus-threads.h D-Bus threads handling |
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3 * |
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4 * Copyright (C) 2002 Red Hat Inc. |
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5 * Portion Copyright © 2008 Nokia Corporation and/or its subsidiary(-ies). All rights reserved. |
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6 * Licensed under the Academic Free License version 2.1 |
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7 * |
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8 * This program is free software; you can redistribute it and/or modify |
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9 * it under the terms of the GNU General Public License as published by |
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10 * the Free Software Foundation; either version 2 of the License, or |
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11 * (at your option) any later version. |
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12 * |
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13 * This program is distributed in the hope that it will be useful, |
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14 * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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16 * GNU General Public License for more details. |
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17 * |
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18 * You should have received a copy of the GNU General Public License |
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19 * along with this program; if not, write to the Free Software |
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20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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21 * |
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22 */ |
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23 #if !defined (DBUS_INSIDE_DBUS_H) && !defined (DBUS_COMPILATION) |
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24 #error "Only <dbus/dbus.h> can be included directly, this file may disappear or change contents." |
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25 #endif |
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26 |
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27 #ifndef DBUS_THREADS_H |
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28 #define DBUS_THREADS_H |
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29 |
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30 #include <dbus/dbus-macros.h> |
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31 #include <dbus/dbus-types.h> |
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32 |
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33 DBUS_BEGIN_DECLS |
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34 |
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35 /** |
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36 * @addtogroup DBusThreads |
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37 * @{ |
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38 */ |
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39 |
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40 /** An opaque mutex type provided by the #DBusThreadFunctions implementation installed by dbus_threads_init(). */ |
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41 typedef struct DBusMutex DBusMutex; |
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42 /** An opaque condition variable type provided by the #DBusThreadFunctions implementation installed by dbus_threads_init(). */ |
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43 typedef struct DBusCondVar DBusCondVar; |
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44 |
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45 /** Deprecated, provide DBusRecursiveMutexNewFunction instead. */ |
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46 typedef DBusMutex* (* DBusMutexNewFunction) (void); |
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47 /** Deprecated, provide DBusRecursiveMutexFreeFunction instead. */ |
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48 typedef void (* DBusMutexFreeFunction) (DBusMutex *mutex); |
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49 /** Deprecated, provide DBusRecursiveMutexLockFunction instead. Return value is lock success, but gets ignored in practice. */ |
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50 typedef dbus_bool_t (* DBusMutexLockFunction) (DBusMutex *mutex); |
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51 /** Deprecated, provide DBusRecursiveMutexUnlockFunction instead. Return value is unlock success, but gets ignored in practice. */ |
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52 typedef dbus_bool_t (* DBusMutexUnlockFunction) (DBusMutex *mutex); |
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53 |
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54 /** Creates a new recursively-lockable mutex, or returns #NULL if not |
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55 * enough memory. Can only fail due to lack of memory. Found in |
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56 * #DBusThreadFunctions. Do not just use PTHREAD_MUTEX_RECURSIVE for |
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57 * this, because it does not save/restore the recursion count when |
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58 * waiting on a condition. libdbus requires the Java-style behavior |
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59 * where the mutex is fully unlocked to wait on a condition. |
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60 */ |
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61 typedef DBusMutex* (* DBusRecursiveMutexNewFunction) (void); |
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62 /** Frees a recursively-lockable mutex. Found in #DBusThreadFunctions. |
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63 */ |
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64 typedef void (* DBusRecursiveMutexFreeFunction) (DBusMutex *mutex); |
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65 /** Locks a recursively-lockable mutex. Found in #DBusThreadFunctions. |
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66 * Can only fail due to lack of memory. |
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67 */ |
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68 typedef void (* DBusRecursiveMutexLockFunction) (DBusMutex *mutex); |
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69 /** Unlocks a recursively-lockable mutex. Found in #DBusThreadFunctions. |
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70 * Can only fail due to lack of memory. |
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71 */ |
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72 typedef void (* DBusRecursiveMutexUnlockFunction) (DBusMutex *mutex); |
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73 |
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74 /** Creates a new condition variable. Found in #DBusThreadFunctions. |
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75 * Can only fail (returning #NULL) due to lack of memory. |
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76 */ |
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77 typedef DBusCondVar* (* DBusCondVarNewFunction) (void); |
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78 /** Frees a condition variable. Found in #DBusThreadFunctions. |
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79 */ |
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80 typedef void (* DBusCondVarFreeFunction) (DBusCondVar *cond); |
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81 |
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82 /** Waits on a condition variable. Found in |
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83 * #DBusThreadFunctions. Must work with either a recursive or |
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84 * nonrecursive mutex, whichever the thread implementation |
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85 * provides. Note that PTHREAD_MUTEX_RECURSIVE does not work with |
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86 * condition variables (does not save/restore the recursion count) so |
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87 * don't try using simply pthread_cond_wait() and a |
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88 * PTHREAD_MUTEX_RECURSIVE to implement this, it won't work right. |
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89 * |
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90 * Has no error conditions. Must succeed if it returns. |
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91 */ |
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92 typedef void (* DBusCondVarWaitFunction) (DBusCondVar *cond, |
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93 DBusMutex *mutex); |
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94 |
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95 /** Waits on a condition variable with a timeout. Found in |
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96 * #DBusThreadFunctions. Returns #TRUE if the wait did not |
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97 * time out, and #FALSE if it did. |
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98 * |
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99 * Has no error conditions. Must succeed if it returns. |
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100 */ |
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101 typedef dbus_bool_t (* DBusCondVarWaitTimeoutFunction) (DBusCondVar *cond, |
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102 DBusMutex *mutex, |
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103 int timeout_milliseconds); |
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104 /** Wakes one waiting thread on a condition variable. Found in #DBusThreadFunctions. |
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105 * |
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106 * Has no error conditions. Must succeed if it returns. |
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107 */ |
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108 typedef void (* DBusCondVarWakeOneFunction) (DBusCondVar *cond); |
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109 |
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110 /** Wakes all waiting threads on a condition variable. Found in #DBusThreadFunctions. |
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111 * |
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112 * Has no error conditions. Must succeed if it returns. |
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113 */ |
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114 typedef void (* DBusCondVarWakeAllFunction) (DBusCondVar *cond); |
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115 |
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116 /** |
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117 * Flags indicating which functions are present in #DBusThreadFunctions. Used to allow |
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118 * the library to detect older callers of dbus_threads_init() if new possible functions |
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119 * are added to #DBusThreadFunctions. |
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120 */ |
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121 typedef enum |
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122 { |
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123 DBUS_THREAD_FUNCTIONS_MUTEX_NEW_MASK = 1 << 0, |
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124 DBUS_THREAD_FUNCTIONS_MUTEX_FREE_MASK = 1 << 1, |
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125 DBUS_THREAD_FUNCTIONS_MUTEX_LOCK_MASK = 1 << 2, |
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126 DBUS_THREAD_FUNCTIONS_MUTEX_UNLOCK_MASK = 1 << 3, |
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127 DBUS_THREAD_FUNCTIONS_CONDVAR_NEW_MASK = 1 << 4, |
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128 DBUS_THREAD_FUNCTIONS_CONDVAR_FREE_MASK = 1 << 5, |
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129 DBUS_THREAD_FUNCTIONS_CONDVAR_WAIT_MASK = 1 << 6, |
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130 DBUS_THREAD_FUNCTIONS_CONDVAR_WAIT_TIMEOUT_MASK = 1 << 7, |
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131 DBUS_THREAD_FUNCTIONS_CONDVAR_WAKE_ONE_MASK = 1 << 8, |
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132 DBUS_THREAD_FUNCTIONS_CONDVAR_WAKE_ALL_MASK = 1 << 9, |
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133 DBUS_THREAD_FUNCTIONS_RECURSIVE_MUTEX_NEW_MASK = 1 << 10, |
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134 DBUS_THREAD_FUNCTIONS_RECURSIVE_MUTEX_FREE_MASK = 1 << 11, |
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135 DBUS_THREAD_FUNCTIONS_RECURSIVE_MUTEX_LOCK_MASK = 1 << 12, |
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136 DBUS_THREAD_FUNCTIONS_RECURSIVE_MUTEX_UNLOCK_MASK = 1 << 13, |
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137 DBUS_THREAD_FUNCTIONS_ALL_MASK = (1 << 14) - 1 |
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138 } DBusThreadFunctionsMask; |
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139 |
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140 /** |
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141 * Functions that must be implemented to make the D-Bus library |
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142 * thread-aware. The recursive mutex functions should be specified |
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143 * rather than the old, deprecated nonrecursive ones. |
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144 * |
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145 * The condition variable functions have to work with recursive |
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146 * mutexes if you provide those, or with nonrecursive mutexes if you |
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147 * provide those. |
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148 * |
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149 * If implementing threads using pthreads, be aware that |
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150 * PTHREAD_MUTEX_RECURSIVE is broken in combination with condition |
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151 * variables. libdbus relies on the Java-style behavior that when |
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152 * waiting on a condition, the recursion count is saved and restored, |
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153 * and the mutex is completely unlocked, not just decremented one |
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154 * level of recursion. |
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155 * |
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156 * Thus with pthreads you probably have to roll your own emulated |
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157 * recursive mutexes, you can't use PTHREAD_MUTEX_RECURSIVE. This is |
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158 * what dbus_threads_init_default() does on platforms that use |
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159 * pthreads. |
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160 */ |
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161 typedef struct |
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162 { |
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163 unsigned int mask; /**< Mask indicating which functions are present. */ |
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164 |
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165 DBusMutexNewFunction mutex_new; /**< Function to create a mutex; optional and deprecated. */ |
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166 DBusMutexFreeFunction mutex_free; /**< Function to free a mutex; optional and deprecated. */ |
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167 DBusMutexLockFunction mutex_lock; /**< Function to lock a mutex; optional and deprecated. */ |
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168 DBusMutexUnlockFunction mutex_unlock; /**< Function to unlock a mutex; optional and deprecated. */ |
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169 |
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170 DBusCondVarNewFunction condvar_new; /**< Function to create a condition variable */ |
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171 DBusCondVarFreeFunction condvar_free; /**< Function to free a condition variable */ |
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172 DBusCondVarWaitFunction condvar_wait; /**< Function to wait on a condition */ |
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173 DBusCondVarWaitTimeoutFunction condvar_wait_timeout; /**< Function to wait on a condition with a timeout */ |
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174 DBusCondVarWakeOneFunction condvar_wake_one; /**< Function to wake one thread waiting on the condition */ |
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175 DBusCondVarWakeAllFunction condvar_wake_all; /**< Function to wake all threads waiting on the condition */ |
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176 |
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177 DBusRecursiveMutexNewFunction recursive_mutex_new; /**< Function to create a recursive mutex */ |
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178 DBusRecursiveMutexFreeFunction recursive_mutex_free; /**< Function to free a recursive mutex */ |
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179 DBusRecursiveMutexLockFunction recursive_mutex_lock; /**< Function to lock a recursive mutex */ |
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180 DBusRecursiveMutexUnlockFunction recursive_mutex_unlock; /**< Function to unlock a recursive mutex */ |
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181 |
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182 void (* padding1) (void); /**< Reserved for future expansion */ |
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183 void (* padding2) (void); /**< Reserved for future expansion */ |
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184 void (* padding3) (void); /**< Reserved for future expansion */ |
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185 void (* padding4) (void); /**< Reserved for future expansion */ |
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186 |
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187 } DBusThreadFunctions; |
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188 |
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189 #ifdef __SYMBIAN32__ |
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190 IMPORT_C |
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191 #endif |
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192 dbus_bool_t dbus_threads_init (const DBusThreadFunctions *functions); |
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193 #ifdef __SYMBIAN32__ |
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194 IMPORT_C |
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195 #endif |
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196 dbus_bool_t dbus_threads_init_default (void); |
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197 |
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198 /** @} */ |
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199 |
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200 DBUS_END_DECLS |
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201 |
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202 #endif /* DBUS_THREADS_H */ |