1 | /** |
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2 | * @file |
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3 | * |
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4 | * @brief Constants and Structures Needed to Declare a Thread Queue |
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5 | * |
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6 | * This include file contains all the constants and structures |
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7 | * needed to declare a thread queue. |
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8 | */ |
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9 | |
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10 | /* |
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11 | * COPYRIGHT (c) 1989-2014. |
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12 | * On-Line Applications Research Corporation (OAR). |
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13 | * |
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14 | * The license and distribution terms for this file may be |
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15 | * found in the file LICENSE in this distribution or at |
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16 | * http://www.rtems.org/license/LICENSE. |
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17 | */ |
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18 | |
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19 | #ifndef _RTEMS_SCORE_THREADQ_H |
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20 | #define _RTEMS_SCORE_THREADQ_H |
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21 | |
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22 | #include <rtems/score/chain.h> |
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23 | #include <rtems/score/isrlock.h> |
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24 | #include <rtems/score/priority.h> |
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25 | #include <rtems/score/rbtree.h> |
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26 | |
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27 | #ifdef __cplusplus |
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28 | extern "C" { |
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29 | #endif |
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30 | |
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31 | /** |
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32 | * @defgroup ScoreThreadQueue Thread Queue Handler |
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33 | * |
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34 | * @ingroup Score |
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35 | * |
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36 | * This handler provides the capability to have threads block in |
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37 | * ordered sets. The sets may be ordered using the FIFO or priority |
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38 | * discipline. |
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39 | */ |
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40 | /**@{*/ |
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41 | |
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42 | typedef struct _Thread_Control Thread_Control; |
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43 | |
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44 | /** |
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45 | * @brief Thread queue heads. |
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46 | * |
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47 | * Each thread is equipped with spare thread queue heads in case it is not |
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48 | * enqueued on a thread queue. The first thread enqueued on a thread queue |
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49 | * will give its spare thread queue heads to that thread queue. The threads |
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50 | * arriving at the queue will add their thread queue heads to the free chain of |
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51 | * the queue heads provided by the first thread enqueued. Once a thread is |
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52 | * dequeued it use the free chain to get new spare thread queue heads. |
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53 | * |
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54 | * Uses a leading underscore in the structure name to allow forward |
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55 | * declarations in standard header files provided by Newlib and GCC. |
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56 | */ |
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57 | typedef struct _Thread_queue_Heads { |
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58 | /** This union contains the data structures used to manage the blocked |
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59 | * set of tasks which varies based upon the discipline. |
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60 | */ |
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61 | union { |
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62 | /** |
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63 | * @brief This is the FIFO discipline list. |
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64 | */ |
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65 | Chain_Control Fifo; |
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66 | |
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67 | /** |
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68 | * @brief This is the set of threads for priority discipline waiting. |
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69 | */ |
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70 | RBTree_Control Priority; |
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71 | } Heads; |
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72 | |
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73 | /** |
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74 | * @brief A chain with free thread queue heads providing the spare thread |
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75 | * queue heads for a thread once it is dequeued. |
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76 | */ |
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77 | Chain_Control Free_chain; |
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78 | |
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79 | /** |
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80 | * @brief A chain node to add these thread queue heads to the free chain of |
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81 | * the thread queue heads dedicated to the thread queue of an object. |
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82 | */ |
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83 | Chain_Node Free_node; |
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84 | } Thread_queue_Heads; |
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85 | |
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86 | typedef struct { |
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87 | /** |
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88 | * @brief The thread queue heads. |
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89 | * |
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90 | * This pointer is NULL, if and only if no threads are enqueued. The first |
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91 | * thread to enqueue will give its spare thread queue heads to this thread |
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92 | * queue. |
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93 | */ |
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94 | Thread_queue_Heads *heads; |
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95 | |
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96 | /** |
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97 | * @brief Lock to protect this thread queue. |
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98 | * |
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99 | * It may be used to protect additional state of the object embedding this |
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100 | * thread queue. |
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101 | * |
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102 | * @see _Thread_queue_Acquire(), _Thread_queue_Acquire_critical() and |
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103 | * _Thread_queue_Release(). |
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104 | */ |
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105 | #if defined(RTEMS_SMP) |
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106 | SMP_ticket_lock_Control Lock; |
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107 | #endif |
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108 | } Thread_queue_Queue; |
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109 | |
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110 | /** |
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111 | * @brief Thread queue priority change operation. |
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112 | * |
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113 | * @param[in] the_thread The thread. |
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114 | * @param[in] new_priority The new priority value. |
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115 | * @param[in] queue The actual thread queue. |
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116 | * |
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117 | * @see Thread_queue_Operations. |
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118 | */ |
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119 | typedef void ( *Thread_queue_Priority_change_operation )( |
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120 | Thread_Control *the_thread, |
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121 | Priority_Control new_priority, |
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122 | Thread_queue_Queue *queue |
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123 | ); |
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124 | |
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125 | /** |
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126 | * @brief Thread queue enqueue operation. |
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127 | * |
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128 | * @param[in] queue The actual thread queue. |
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129 | * @param[in] the_thread The thread to enqueue on the queue. |
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130 | * |
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131 | * @see _Thread_Wait_set_operations(). |
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132 | */ |
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133 | typedef void ( *Thread_queue_Enqueue_operation )( |
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134 | Thread_queue_Queue *queue, |
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135 | Thread_Control *the_thread |
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136 | ); |
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137 | |
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138 | /** |
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139 | * @brief Thread queue extract operation. |
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140 | * |
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141 | * @param[in] queue The actual thread queue. |
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142 | * @param[in] the_thread The thread to extract from the thread queue. |
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143 | * |
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144 | * @see _Thread_Wait_set_operations(). |
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145 | */ |
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146 | typedef void ( *Thread_queue_Extract_operation )( |
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147 | Thread_queue_Queue *queue, |
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148 | Thread_Control *the_thread |
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149 | ); |
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150 | |
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151 | /** |
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152 | * @brief Thread queue first operation. |
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153 | * |
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154 | * @param[in] heads The thread queue heads. |
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155 | * |
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156 | * @retval NULL No thread is present on the thread queue. |
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157 | * @retval first The first thread of the thread queue according to the insert |
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158 | * order. This thread remains on the thread queue. |
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159 | * |
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160 | * @see _Thread_Wait_set_operations(). |
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161 | */ |
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162 | typedef Thread_Control *( *Thread_queue_First_operation )( |
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163 | Thread_queue_Heads *heads |
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164 | ); |
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165 | |
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166 | /** |
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167 | * @brief Thread queue operations. |
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168 | * |
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169 | * @see _Thread_wait_Set_operations(). |
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170 | */ |
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171 | typedef struct { |
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172 | /** |
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173 | * @brief Thread queue priority change operation. |
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174 | * |
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175 | * Called by _Thread_Change_priority() to notify a thread about a priority |
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176 | * change. In case this thread waits currently for a resource the handler |
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177 | * may adjust its data structures according to the new priority value. This |
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178 | * handler must not be NULL, instead the default handler |
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179 | * _Thread_Do_nothing_priority_change() should be used in case nothing needs |
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180 | * to be done during a priority change. |
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181 | */ |
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182 | Thread_queue_Priority_change_operation priority_change; |
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183 | |
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184 | /** |
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185 | * @brief Thread queue enqueue operation. |
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186 | * |
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187 | * Called by object routines to enqueue the thread. |
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188 | */ |
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189 | Thread_queue_Enqueue_operation enqueue; |
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190 | |
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191 | /** |
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192 | * @brief Thread queue extract operation. |
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193 | * |
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194 | * Called by object routines to extract a thread from a thread queue. |
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195 | */ |
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196 | Thread_queue_Extract_operation extract; |
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197 | |
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198 | /** |
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199 | * @brief Thread queue first operation. |
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200 | */ |
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201 | Thread_queue_First_operation first; |
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202 | } Thread_queue_Operations; |
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203 | |
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204 | /** |
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205 | * The following enumerated type details all of the disciplines |
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206 | * supported by the Thread Queue Handler. |
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207 | */ |
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208 | typedef enum { |
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209 | THREAD_QUEUE_DISCIPLINE_FIFO, /* FIFO queue discipline */ |
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210 | THREAD_QUEUE_DISCIPLINE_PRIORITY /* PRIORITY queue discipline */ |
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211 | } Thread_queue_Disciplines; |
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212 | |
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213 | /** |
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214 | * This is the structure used to manage sets of tasks which are blocked |
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215 | * waiting to acquire a resource. |
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216 | */ |
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217 | typedef struct { |
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218 | /** |
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219 | * @brief The actual thread queue. |
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220 | */ |
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221 | Thread_queue_Queue Queue; |
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222 | |
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223 | #if defined(RTEMS_SMP) && defined(RTEMS_PROFILING) |
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224 | SMP_lock_Stats Lock_stats; |
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225 | #endif |
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226 | |
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227 | /** |
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228 | * @brief The operations for the actual thread queue. |
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229 | */ |
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230 | const Thread_queue_Operations *operations; |
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231 | } Thread_queue_Control; |
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232 | |
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233 | /**@}*/ |
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234 | |
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235 | #ifdef __cplusplus |
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236 | } |
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237 | #endif |
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238 | |
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239 | #endif |
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240 | /* end of include file */ |
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