1 | // |
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2 | // Mutex.h |
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3 | // |
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4 | // $Id: //poco/1.3/Foundation/include/Poco/Mutex.h#2 $ |
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5 | // |
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6 | // Library: Foundation |
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7 | // Package: Threading |
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8 | // Module: Mutex |
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9 | // |
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10 | // Definition of the Mutex and FastMutex classes. |
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11 | // |
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12 | // Copyright (c) 2004-2008, Applied Informatics Software Engineering GmbH. |
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13 | // and Contributors. |
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14 | // |
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15 | // Permission is hereby granted, free of charge, to any person or organization |
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16 | // obtaining a copy of the software and accompanying documentation covered by |
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17 | // this license (the "Software") to use, reproduce, display, distribute, |
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18 | // execute, and transmit the Software, and to prepare derivative works of the |
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19 | // Software, and to permit third-parties to whom the Software is furnished to |
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20 | // do so, all subject to the following: |
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21 | // |
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22 | // The copyright notices in the Software and this entire statement, including |
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23 | // the above license grant, this restriction and the following disclaimer, |
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24 | // must be included in all copies of the Software, in whole or in part, and |
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25 | // all derivative works of the Software, unless such copies or derivative |
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26 | // works are solely in the form of machine-executable object code generated by |
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27 | // a source language processor. |
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28 | // |
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29 | // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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30 | // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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31 | // FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT |
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32 | // SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE |
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33 | // FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE, |
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34 | // ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER |
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35 | // DEALINGS IN THE SOFTWARE. |
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36 | // |
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37 | |
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38 | |
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39 | #ifndef Foundation_Mutex_INCLUDED |
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40 | #define Foundation_Mutex_INCLUDED |
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41 | |
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42 | |
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43 | #include "Poco/Foundation.h" |
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44 | #include "Poco/Exception.h" |
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45 | #include "Poco/ScopedLock.h" |
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46 | |
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47 | |
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48 | #if defined(POCO_OS_FAMILY_WINDOWS) |
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49 | #include "Poco/Mutex_WIN32.h" |
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50 | #else |
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51 | #include "Poco/Mutex_POSIX.h" |
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52 | #endif |
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53 | |
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54 | |
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55 | namespace Poco { |
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56 | |
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57 | |
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58 | class Foundation_API Mutex: private MutexImpl |
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59 | /// A Mutex (mutual exclusion) is a synchronization |
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60 | /// mechanism used to control access to a shared resource |
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61 | /// in a concurrent (multithreaded) scenario. |
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62 | /// Mutexes are recursive, that is, the same mutex can be |
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63 | /// locked multiple times by the same thread (but, of course, |
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64 | /// not by other threads). |
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65 | /// Using the ScopedLock class is the preferred way to automatically |
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66 | /// lock and unlock a mutex. |
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67 | { |
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68 | public: |
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69 | typedef Poco::ScopedLock<Mutex> ScopedLock; |
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70 | |
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71 | Mutex(); |
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72 | /// creates the Mutex. |
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73 | |
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74 | ~Mutex(); |
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75 | /// destroys the Mutex. |
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76 | |
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77 | void lock(); |
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78 | /// Locks the mutex. Blocks if the mutex |
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79 | /// is held by another thread. |
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80 | |
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81 | void lock(long milliseconds); |
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82 | /// Locks the mutex. Blocks up to the given number of milliseconds |
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83 | /// if the mutex is held by another thread. Throws a TimeoutException |
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84 | /// if the mutex can not be locked within the given timeout. |
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85 | /// |
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86 | /// Performance Note: On most platforms (including Windows), this member function is |
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87 | /// implemented using a loop calling (the equivalent of) tryLock() and Thread::sleep(). |
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88 | /// On POSIX platforms that support pthread_mutex_timedlock(), this is used. |
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89 | |
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90 | bool tryLock(); |
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91 | /// Tries to lock the mutex. Returns false immediately |
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92 | /// if the mutex is already held by another thread. |
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93 | /// Returns true if the mutex was successfully locked. |
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94 | |
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95 | bool tryLock(long milliseconds); |
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96 | /// Locks the mutex. Blocks up to the given number of milliseconds |
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97 | /// if the mutex is held by another thread. |
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98 | /// Returns true if the mutex was successfully locked. |
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99 | /// |
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100 | /// Performance Note: On most platforms (including Windows), this member function is |
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101 | /// implemented using a loop calling (the equivalent of) tryLock() and Thread::sleep(). |
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102 | /// On POSIX platforms that support pthread_mutex_timedlock(), this is used. |
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103 | |
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104 | void unlock(); |
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105 | /// Unlocks the mutex so that it can be acquired by |
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106 | /// other threads. |
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107 | |
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108 | private: |
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109 | Mutex(const Mutex&); |
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110 | Mutex& operator = (const Mutex&); |
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111 | }; |
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112 | |
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113 | |
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114 | class Foundation_API FastMutex: private FastMutexImpl |
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115 | /// A FastMutex (mutual exclusion) is similar to a Mutex. |
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116 | /// Unlike a Mutex, however, a FastMutex is not recursive, |
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117 | /// which means that a deadlock will occur if the same |
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118 | /// thread tries to lock a mutex it has already locked again. |
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119 | /// Locking a FastMutex is faster than locking a recursive Mutex. |
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120 | /// Using the ScopedLock class is the preferred way to automatically |
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121 | /// lock and unlock a mutex. |
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122 | { |
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123 | public: |
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124 | typedef Poco::ScopedLock<FastMutex> ScopedLock; |
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125 | |
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126 | FastMutex(); |
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127 | /// creates the Mutex. |
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128 | |
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129 | ~FastMutex(); |
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130 | /// destroys the Mutex. |
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131 | |
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132 | void lock(); |
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133 | /// Locks the mutex. Blocks if the mutex |
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134 | /// is held by another thread. |
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135 | |
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136 | void lock(long milliseconds); |
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137 | /// Locks the mutex. Blocks up to the given number of milliseconds |
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138 | /// if the mutex is held by another thread. Throws a TimeoutException |
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139 | /// if the mutex can not be locked within the given timeout. |
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140 | /// |
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141 | /// Performance Note: On most platforms (including Windows), this member function is |
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142 | /// implemented using a loop calling (the equivalent of) tryLock() and Thread::sleep(). |
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143 | /// On POSIX platforms that support pthread_mutex_timedlock(), this is used. |
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144 | |
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145 | bool tryLock(); |
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146 | /// Tries to lock the mutex. Returns false immediately |
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147 | /// if the mutex is already held by another thread. |
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148 | /// Returns true if the mutex was successfully locked. |
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149 | |
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150 | bool tryLock(long milliseconds); |
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151 | /// Locks the mutex. Blocks up to the given number of milliseconds |
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152 | /// if the mutex is held by another thread. |
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153 | /// Returns true if the mutex was successfully locked. |
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154 | /// |
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155 | /// Performance Note: On most platforms (including Windows), this member function is |
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156 | /// implemented using a loop calling (the equivalent of) tryLock() and Thread::sleep(). |
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157 | /// On POSIX platforms that support pthread_mutex_timedlock(), this is used. |
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158 | |
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159 | void unlock(); |
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160 | /// Unlocks the mutex so that it can be acquired by |
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161 | /// other threads. |
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162 | |
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163 | private: |
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164 | FastMutex(const FastMutex&); |
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165 | FastMutex& operator = (const FastMutex&); |
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166 | }; |
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167 | |
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168 | |
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169 | // |
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170 | // inlines |
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171 | // |
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172 | inline void Mutex::lock() |
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173 | { |
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174 | lockImpl(); |
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175 | } |
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176 | |
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177 | |
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178 | inline void Mutex::lock(long milliseconds) |
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179 | { |
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180 | if (!tryLockImpl(milliseconds)) |
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181 | throw TimeoutException(); |
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182 | } |
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183 | |
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184 | |
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185 | inline bool Mutex::tryLock() |
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186 | { |
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187 | return tryLockImpl(); |
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188 | } |
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189 | |
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190 | |
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191 | inline bool Mutex::tryLock(long milliseconds) |
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192 | { |
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193 | return tryLockImpl(milliseconds); |
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194 | } |
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195 | |
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196 | |
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197 | inline void Mutex::unlock() |
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198 | { |
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199 | unlockImpl(); |
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200 | } |
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201 | |
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202 | |
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203 | inline void FastMutex::lock() |
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204 | { |
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205 | lockImpl(); |
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206 | } |
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207 | |
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208 | |
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209 | inline void FastMutex::lock(long milliseconds) |
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210 | { |
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211 | if (!tryLockImpl(milliseconds)) |
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212 | throw TimeoutException(); |
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213 | } |
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214 | |
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215 | |
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216 | inline bool FastMutex::tryLock() |
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217 | { |
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218 | return tryLockImpl(); |
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219 | } |
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220 | |
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221 | |
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222 | inline bool FastMutex::tryLock(long milliseconds) |
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223 | { |
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224 | return tryLockImpl(milliseconds); |
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225 | } |
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226 | |
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227 | |
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228 | inline void FastMutex::unlock() |
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229 | { |
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230 | unlockImpl(); |
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231 | } |
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232 | |
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233 | |
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234 | } // namespace Poco |
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235 | |
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236 | |
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237 | #endif // Foundation_Mutex_INCLUDED |
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