1 | /** |
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2 | * @file |
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3 | * |
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4 | * @ingroup RTEMSScoreMessageQueue |
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5 | * |
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6 | * @brief Constants and Structures Associated with the Message Queue Handler. |
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7 | * |
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8 | * This include file contains all the constants and structures associated |
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9 | * with the Message queue Handler. |
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10 | */ |
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11 | |
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12 | /* |
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13 | * COPYRIGHT (c) 1989-2009. |
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14 | * On-Line Applications Research Corporation (OAR). |
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15 | * |
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16 | * The license and distribution terms for this file may be |
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17 | * found in the file LICENSE in this distribution or at |
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18 | * http://www.rtems.org/license/LICENSE. |
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19 | */ |
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20 | |
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21 | #ifndef _RTEMS_SCORE_COREMSG_H |
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22 | #define _RTEMS_SCORE_COREMSG_H |
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23 | |
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24 | #include <rtems/score/chain.h> |
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25 | #include <rtems/score/isrlock.h> |
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26 | #include <rtems/score/threadq.h> |
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27 | #include <rtems/score/watchdog.h> |
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28 | |
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29 | #ifdef __cplusplus |
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30 | extern "C" { |
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31 | #endif |
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32 | |
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33 | /** |
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34 | * @defgroup RTEMSScoreMessageQueue Message Queue Handler |
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35 | * |
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36 | * @ingroup RTEMSScore |
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37 | * |
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38 | * @brief Message Queue Handler |
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39 | * |
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40 | * This handler encapsulates functionality which provides the foundation |
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41 | * Message Queue services used in all of the APIs supported by RTEMS. |
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42 | * |
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43 | * @{ |
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44 | */ |
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45 | |
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46 | /** |
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47 | * This macro is defined when an API is enabled that requires that the |
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48 | * Message Queue Handler include support for priority based enqueuing |
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49 | * of messages. |
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50 | */ |
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51 | #define RTEMS_SCORE_COREMSG_ENABLE_MESSAGE_PRIORITY |
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52 | |
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53 | #if defined(RTEMS_POSIX_API) |
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54 | /** |
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55 | * This macro is defined when an API is enabled that requires that the |
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56 | * Message Queue Handler include support for notification of enqueuing |
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57 | * a message. |
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58 | */ |
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59 | #define RTEMS_SCORE_COREMSG_ENABLE_NOTIFICATION |
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60 | #endif |
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61 | |
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62 | /** |
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63 | * This macro is defined when an API is enabled that requires the |
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64 | * Message Queue Handler include support for blocking send operations. |
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65 | */ |
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66 | #define RTEMS_SCORE_COREMSG_ENABLE_BLOCKING_SEND |
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67 | |
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68 | typedef struct CORE_message_queue_Control CORE_message_queue_Control; |
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69 | |
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70 | /** |
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71 | * @brief Data types needed to manipulate the contents of message buffers. |
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72 | * |
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73 | * The following defines the data types needed to manipulate |
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74 | * the contents of message buffers. |
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75 | * |
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76 | * @note The buffer field is normally longer than a single uint32_t |
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77 | * but since messages are variable length we just make a ptr to 1. |
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78 | */ |
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79 | typedef struct { |
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80 | /** This field is the size of this message. */ |
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81 | size_t size; |
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82 | /** This field contains the actual message. */ |
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83 | uint32_t buffer[1]; |
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84 | } CORE_message_queue_Buffer; |
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85 | |
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86 | /** |
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87 | * @brief The organization of a message buffer. |
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88 | * |
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89 | * The following records define the organization of a message |
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90 | * buffer. |
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91 | */ |
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92 | typedef struct { |
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93 | /** This element allows this structure to be placed on chains. */ |
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94 | Chain_Node Node; |
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95 | #if defined(RTEMS_SCORE_COREMSG_ENABLE_MESSAGE_PRIORITY) |
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96 | /** This field is the priority of this message. */ |
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97 | int priority; |
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98 | #endif |
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99 | /** This field points to the contents of the message. */ |
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100 | CORE_message_queue_Buffer Contents; |
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101 | } CORE_message_queue_Buffer_control; |
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102 | |
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103 | /** |
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104 | * @brief The possible blocking disciplines for a message queue. |
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105 | * |
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106 | * This enumerated types defines the possible blocking disciplines |
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107 | * for a message queue. |
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108 | */ |
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109 | typedef enum { |
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110 | /** This value indicates that blocking tasks are in FIFO order. */ |
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111 | CORE_MESSAGE_QUEUE_DISCIPLINES_FIFO, |
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112 | /** This value indicates that blocking tasks are in priority order. */ |
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113 | CORE_MESSAGE_QUEUE_DISCIPLINES_PRIORITY |
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114 | } CORE_message_queue_Disciplines; |
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115 | |
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116 | #if defined(RTEMS_SCORE_COREMSG_ENABLE_NOTIFICATION) |
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117 | /** |
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118 | * @brief Type for a notification handler. |
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119 | * |
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120 | * The following defines the type for a Notification handler. A |
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121 | * notification handler is invoked when the message queue makes a |
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122 | * 0->1 transition on pending messages. |
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123 | */ |
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124 | typedef void (*CORE_message_queue_Notify_Handler)( |
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125 | CORE_message_queue_Control *, |
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126 | Thread_queue_Context * |
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127 | ); |
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128 | #endif |
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129 | |
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130 | /** |
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131 | * @brief Control block used to manage each message queue. |
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132 | * |
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133 | * The following defines the control block used to manage each |
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134 | * Message Queue. |
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135 | */ |
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136 | struct CORE_message_queue_Control { |
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137 | /** This field is the Waiting Queue used to manage the set of tasks |
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138 | * which are blocked waiting to receive a message from this queue. |
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139 | */ |
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140 | Thread_queue_Control Wait_queue; |
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141 | |
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142 | /** |
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143 | * @brief The thread queue operations according to the blocking discipline. |
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144 | */ |
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145 | const Thread_queue_Operations *operations; |
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146 | |
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147 | /** This element is maximum number of messages which may be pending |
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148 | * at any given time. |
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149 | */ |
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150 | uint32_t maximum_pending_messages; |
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151 | /** This element is the number of messages which are currently pending. |
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152 | */ |
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153 | uint32_t number_of_pending_messages; |
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154 | /** This is the size in bytes of the largest message which may be |
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155 | * sent via this queue. |
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156 | */ |
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157 | size_t maximum_message_size; |
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158 | /** This chain is the set of pending messages. It may be ordered by |
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159 | * message priority or in FIFO order. |
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160 | */ |
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161 | Chain_Control Pending_messages; |
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162 | /** This is the address of the memory allocated for message buffers. |
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163 | * It is allocated are part of message queue initialization and freed |
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164 | * as part of destroying it. |
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165 | */ |
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166 | CORE_message_queue_Buffer *message_buffers; |
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167 | #if defined(RTEMS_SCORE_COREMSG_ENABLE_NOTIFICATION) |
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168 | /** This is the routine invoked when the message queue transitions |
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169 | * from zero (0) messages pending to one (1) message pending. |
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170 | */ |
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171 | CORE_message_queue_Notify_Handler notify_handler; |
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172 | #endif |
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173 | /** This chain is the set of inactive messages. A message is inactive |
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174 | * when it does not contain a pending message. |
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175 | */ |
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176 | Chain_Control Inactive_messages; |
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177 | }; |
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178 | |
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179 | /** @} */ |
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180 | |
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181 | #ifdef __cplusplus |
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182 | } |
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183 | #endif |
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184 | |
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185 | #endif |
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186 | /* end of include file */ |
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