1 | @c |
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2 | @c COPYRIGHT (c) 1988-2002. |
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3 | @c On-Line Applications Research Corporation (OAR). |
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4 | @c All rights reserved. |
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5 | @c |
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6 | @c $Id$ |
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7 | @c |
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8 | |
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9 | @chapter User Extensions Manager |
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10 | |
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11 | @cindex user extensions |
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12 | |
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13 | @section Introduction |
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14 | |
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15 | The RTEMS User Extensions Manager allows the |
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16 | application developer to augment the executive by allowing them |
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17 | to supply extension routines which are invoked at critical |
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18 | system events. The directives provided by the user extensions |
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19 | manager are: |
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20 | |
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21 | @itemize @bullet |
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22 | @item @code{@value{DIRPREFIX}extension_create} - Create an extension set |
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23 | @item @code{@value{DIRPREFIX}extension_ident} - Get ID of an extension set |
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24 | @item @code{@value{DIRPREFIX}extension_delete} - Delete an extension set |
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25 | @end itemize |
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26 | |
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27 | @section Background |
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28 | |
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29 | User extension routines are invoked when the |
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30 | following system events occur: |
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31 | |
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32 | @itemize @bullet |
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33 | @item Task creation |
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34 | @item Task initiation |
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35 | @item Task reinitiation |
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36 | @item Task deletion |
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37 | @item Task context switch |
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38 | @item Post task context switch |
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39 | @item Task begin |
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40 | @item Task exits |
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41 | @item Fatal error detection |
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42 | @end itemize |
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43 | |
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44 | These extensions are invoked as a function with |
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45 | arguments that are appropriate to the system event. |
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46 | |
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47 | @subsection Extension Sets |
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48 | |
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49 | @cindex extension set |
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50 | |
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51 | An extension set is defined as a set of routines |
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52 | which are invoked at each of the critical system events at which |
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53 | user extension routines are invoked. Together a set of these |
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54 | routines typically perform a specific functionality such as |
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55 | performance monitoring or debugger support. RTEMS is informed of |
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56 | the entry points which constitute an extension set via the |
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57 | following @value{STRUCTURE}: |
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58 | |
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59 | @findex rtems_extensions_table |
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60 | @ifset is-C |
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61 | @example |
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62 | @group |
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63 | typedef struct @{ |
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64 | rtems_task_create_extension thread_create; |
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65 | rtems_task_start_extension thread_start; |
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66 | rtems_task_restart_extension thread_restart; |
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67 | rtems_task_delete_extension thread_delete; |
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68 | rtems_task_switch_extension thread_switch; |
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69 | rtems_task_begin_extension thread_begin; |
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70 | rtems_task_exitted_extension thread_exitted; |
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71 | rtems_fatal_extension fatal; |
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72 | @} rtems_extensions_table; |
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73 | @end group |
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74 | @end example |
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75 | @end ifset |
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76 | |
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77 | @ifset is-Ada |
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78 | @example |
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79 | type Extensions_Table is |
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80 | record |
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81 | Task_Create : RTEMS.Task_Create_Extension; |
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82 | Task_Start : RTEMS.Task_Start_Extension; |
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83 | Task_Restart : RTEMS.Task_Restart_Extension; |
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84 | Task_Delete : RTEMS.Task_Delete_Extension; |
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85 | Task_Switch : RTEMS.Task_Switch_Extension; |
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86 | Task_Post_Switch : RTEMS.Task_Post_Switch_Extension; |
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87 | Task_Begin : RTEMS.Task_Begin_Extension; |
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88 | Task_Exitted : RTEMS.Task_Exitted_Extension; |
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89 | Fatal : RTEMS.Fatal_Error_Extension; |
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90 | end record; |
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91 | @end example |
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92 | @end ifset |
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93 | |
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94 | |
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95 | RTEMS allows the user to have multiple extension sets |
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96 | active at the same time. First, a single static extension set |
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97 | may be defined as the application's User Extension Table which |
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98 | is included as part of the Configuration Table. This extension |
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99 | set is active for the entire life of the system and may not be |
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100 | deleted. This extension set is especially important because it |
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101 | is the only way the application can provided a FATAL error |
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102 | extension which is invoked if RTEMS fails during the |
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103 | initialize_executive directive. The static extension set is |
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104 | optional and may be configured as NULL if no static extension |
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105 | set is required. |
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106 | |
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107 | Second, the user can install dynamic extensions using |
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108 | the @code{@value{DIRPREFIX}extension_create} |
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109 | directive. These extensions are RTEMS |
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110 | objects in that they have a name, an ID, and can be dynamically |
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111 | created and deleted. In contrast to the static extension set, |
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112 | these extensions can only be created and installed after the |
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113 | initialize_executive directive successfully completes execution. |
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114 | Dynamic extensions are useful for encapsulating the |
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115 | functionality of an extension set. For example, the application |
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116 | could use extensions to manage a special coprocessor, do |
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117 | performance monitoring, and to do stack bounds checking. Each |
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118 | of these extension sets could be written and installed |
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119 | independently of the others. |
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120 | |
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121 | All user extensions are optional and RTEMS places no |
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122 | naming restrictions on the user. The user extension entry points |
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123 | are copied into an internal RTEMS structure. This means the user |
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124 | does not need to keep the table after creating it, and changing the |
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125 | handler entry points dynamically in a table once created has no |
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126 | effect. Creating a table local to a function can save space in |
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127 | space limited applications. |
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128 | |
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129 | Extension switches do not effect the context switch overhead if |
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130 | no switch handler is installed. |
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131 | |
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132 | @subsection TCB Extension Area |
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133 | |
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134 | @cindex TCB extension area |
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135 | |
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136 | RTEMS provides for a pointer to a user-defined data |
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137 | area for each extension set to be linked to each task's control |
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138 | block. This set of pointers is an extension of the TCB and can |
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139 | be used to store additional data required by the user's |
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140 | extension functions. It is also possible for a user extension |
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141 | to utilize the notepad locations associated with each task |
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142 | although this may conflict with application usage of those |
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143 | particular notepads. |
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144 | |
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145 | The TCB extension is an array of pointers in the TCB. The |
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146 | index into the table can be obtained from the extension id |
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147 | returned when the extension is created: |
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148 | |
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149 | @findex rtems extensions table index |
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150 | @ifset is-C |
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151 | @example |
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152 | @group |
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153 | index = rtems_get_index(extension_id); |
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154 | @end group |
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155 | @end example |
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156 | @end ifset |
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157 | |
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158 | @ifset is-Ada |
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159 | @example |
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160 | There is currently no example for Ada. |
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161 | @end example |
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162 | @end ifset |
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163 | |
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164 | The number of pointers in the area is the same as the number of |
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165 | user extension sets configured. This allows an application to |
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166 | augment the TCB with user-defined information. For example, an |
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167 | application could implement task profiling by storing timing |
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168 | statistics in the TCB's extended memory area. When a task |
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169 | context switch is being executed, the TASK_SWITCH extension |
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170 | could read a real-time clock to calculate how long the task |
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171 | being swapped out has run as well as timestamp the starting time |
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172 | for the task being swapped in. |
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173 | |
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174 | If used, the extended memory area for the TCB should |
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175 | be allocated and the TCB extension pointer should be set at the |
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176 | time the task is created or started by either the TASK_CREATE or |
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177 | TASK_START extension. The application is responsible for |
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178 | managing this extended memory area for the TCBs. The memory may |
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179 | be reinitialized by the TASK_RESTART extension and should be |
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180 | deallocated by the TASK_DELETE extension when the task is |
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181 | deleted. Since the TCB extension buffers would most likely be |
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182 | of a fixed size, the RTEMS partition manager could be used to |
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183 | manage the application's extended memory area. The application |
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184 | could create a partition of fixed size TCB extension buffers and |
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185 | use the partition manager's allocation and deallocation |
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186 | directives to obtain and release the extension buffers. |
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187 | |
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188 | @subsection Extensions |
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189 | |
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190 | The sections that follow will contain a description |
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191 | of each extension. Each section will contain a prototype of a |
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192 | function with the appropriate calling sequence for the |
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193 | corresponding extension. The names given for the @value{LANGUAGE} |
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194 | @value{ROUTINE} and |
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195 | its arguments are all defined by the user. The names used in |
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196 | the examples were arbitrarily chosen and impose no naming |
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197 | conventions on the user. |
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198 | |
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199 | @subsubsection TASK_CREATE Extension |
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200 | |
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201 | The TASK_CREATE extension directly corresponds to the |
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202 | @code{@value{DIRPREFIX}task_create} directive. If this extension |
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203 | is defined in any |
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204 | static or dynamic extension set and a task is being created, |
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205 | then the extension routine will automatically be invoked by |
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206 | RTEMS. The extension should have a prototype similar to the |
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207 | following: |
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208 | |
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209 | @findex rtems_task_create_extension |
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210 | @findex rtems_extension |
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211 | @ifset is-C |
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212 | @example |
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213 | boolean user_task_create( |
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214 | rtems_tcb *current_task, |
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215 | rtems_tcb *new_task |
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216 | ); |
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217 | @end example |
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218 | @end ifset |
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219 | |
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220 | @ifset is-Ada |
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221 | @example |
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222 | function User_Task_Create ( |
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223 | Current_Task : in RTEMS.TCB_Pointer; |
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224 | New_Task : in RTEMS.TCB_Pointer |
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225 | ) returns Boolean; |
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226 | @end example |
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227 | @end ifset |
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228 | |
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229 | where @code{current_task} can be used to access the TCB for |
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230 | the currently executing task, and new_task can be used to access |
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231 | the TCB for the new task being created. This extension is |
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232 | invoked from the @code{@value{DIRPREFIX}task_create} |
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233 | directive after @code{new_task} has been |
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234 | completely initialized, but before it is placed on a ready TCB |
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235 | chain. |
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236 | |
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237 | The user extension is expected to return the boolean |
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238 | value @code{TRUE} if it successfully executed and |
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239 | @code{FALSE} otherwise. A task create user extension |
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240 | will frequently attempt to allocate resources. If this |
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241 | allocation fails, then the extension should return |
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242 | @code{FALSE} and the entire task create operation |
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243 | will fail. |
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244 | |
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245 | @subsubsection TASK_START Extension |
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246 | |
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247 | The TASK_START extension directly corresponds to the |
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248 | task_start directive. If this extension is defined in any |
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249 | static or dynamic extension set and a task is being started, |
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250 | then the extension routine will automatically be invoked by |
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251 | RTEMS. The extension should have a prototype similar to the |
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252 | following: |
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253 | |
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254 | @findex rtems_task_start_extension |
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255 | @ifset is-C |
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256 | @example |
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257 | rtems_extension user_task_start( |
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258 | rtems_tcb *current_task, |
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259 | rtems_tcb *started_task |
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260 | ); |
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261 | @end example |
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262 | @end ifset |
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263 | |
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264 | @ifset is-Ada |
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265 | @example |
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266 | procedure User_Task_Start ( |
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267 | Current_Task : in RTEMS.TCB_Pointer; |
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268 | Started_Task : in RTEMS.TCB_Pointer |
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269 | ); |
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270 | @end example |
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271 | @end ifset |
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272 | |
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273 | where current_task can be used to access the TCB for |
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274 | the currently executing task, and started_task can be used to |
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275 | access the TCB for the dormant task being started. This |
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276 | extension is invoked from the task_start directive after |
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277 | started_task has been made ready to start execution, but before |
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278 | it is placed on a ready TCB chain. |
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279 | |
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280 | @subsubsection TASK_RESTART Extension |
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281 | |
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282 | The TASK_RESTART extension directly corresponds to |
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283 | the task_restart directive. If this extension is defined in any |
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284 | static or dynamic extension set and a task is being restarted, |
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285 | then the extension should have a prototype similar to the |
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286 | following: |
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287 | |
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288 | @findex rtems_task_restart_extension |
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289 | @ifset is-C |
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290 | @example |
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291 | rtems_extension user_task_restart( |
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292 | rtems_tcb *current_task, |
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293 | rtems_tcb *restarted_task |
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294 | ); |
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295 | @end example |
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296 | @end ifset |
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297 | |
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298 | @ifset is-Ada |
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299 | @example |
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300 | procedure User_Task_Restart ( |
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301 | Current_Task : in RTEMS.TCB_Pointer; |
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302 | Restarted_Task : in RTEMS.TCB_Pointer |
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303 | ); |
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304 | @end example |
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305 | @end ifset |
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306 | |
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307 | where current_task can be used to access the TCB for |
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308 | the currently executing task, and restarted_task can be used to |
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309 | access the TCB for the task being restarted. This extension is |
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310 | invoked from the task_restart directive after restarted_task has |
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311 | been made ready to start execution, but before it is placed on a |
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312 | ready TCB chain. |
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313 | |
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314 | @subsubsection TASK_DELETE Extension |
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315 | |
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316 | The TASK_DELETE extension is associated with the |
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317 | task_delete directive. If this extension is defined in any |
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318 | static or dynamic extension set and a task is being deleted, |
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319 | then the extension routine will automatically be invoked by |
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320 | RTEMS. The extension should have a prototype similar to the |
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321 | following: |
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322 | |
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323 | @findex rtems_task_delete_extension |
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324 | @ifset is-C |
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325 | @example |
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326 | rtems_extension user_task_delete( |
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327 | rtems_tcb *current_task, |
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328 | rtems_tcb *deleted_task |
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329 | ); |
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330 | @end example |
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331 | @end ifset |
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332 | |
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333 | @ifset is-Ada |
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334 | @example |
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335 | procedure User_Task_Delete ( |
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336 | Current_Task : in RTEMS.TCB_Pointer; |
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337 | Deleted_Task : in RTEMS.TCB_Pointer |
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338 | ); |
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339 | @end example |
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340 | @end ifset |
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341 | |
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342 | where current_task can be used to access the TCB for |
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343 | the currently executing task, and deleted_task can be used to |
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344 | access the TCB for the task being deleted. This extension is |
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345 | invoked from the task_delete directive after the TCB has been |
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346 | removed from a ready TCB chain, but before all its resources |
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347 | including the TCB have been returned to their respective free |
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348 | pools. This extension should not call any RTEMS directives if a |
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349 | task is deleting itself (current_task is equal to deleted_task). |
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350 | |
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351 | @subsubsection TASK_SWITCH Extension |
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352 | |
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353 | The TASK_SWITCH extension corresponds to a task |
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354 | context switch. If this extension is defined in any static or |
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355 | dynamic extension set and a task context switch is in progress, |
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356 | then the extension routine will automatically be invoked by |
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357 | RTEMS. The extension should have a prototype similar to the |
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358 | following: |
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359 | |
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360 | @findex rtems_task_switch_extension |
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361 | @ifset is-C |
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362 | @example |
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363 | rtems_extension user_task_switch( |
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364 | rtems_tcb *current_task, |
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365 | rtems_tcb *heir_task |
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366 | ); |
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367 | @end example |
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368 | @end ifset |
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369 | |
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370 | @ifset is-Ada |
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371 | @example |
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372 | procedure User_Task_Switch ( |
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373 | Current_Task : in RTEMS.TCB_Pointer; |
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374 | Heir_Task : in RTEMS.TCB_Pointer |
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375 | ); |
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376 | @end example |
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377 | @end ifset |
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378 | |
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379 | where current_task can be used to access the TCB for |
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380 | the task that is being swapped out, and heir_task can be used to |
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381 | access the TCB for the task being swapped in. This extension is |
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382 | invoked from RTEMS' dispatcher routine after the current_task |
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383 | context has been saved, but before the heir_task context has |
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384 | been restored. This extension should not call any RTEMS |
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385 | directives. |
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386 | |
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387 | @subsubsection TASK_BEGIN Extension |
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388 | |
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389 | The TASK_BEGIN extension is invoked when a task |
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390 | begins execution. It is invoked immediately before the body of |
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391 | the starting procedure and executes in the context in the task. |
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392 | This user extension have a prototype similar to the following: |
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393 | |
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394 | @findex rtems_task_begin_extension |
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395 | @ifset is-C |
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396 | @example |
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397 | rtems_extension user_task_begin( |
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398 | rtems_tcb *current_task |
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399 | ); |
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400 | @end example |
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401 | @end ifset |
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402 | |
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403 | @ifset is-Ada |
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404 | @example |
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405 | procedure User_Task_Begin ( |
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406 | Current_Task : in RTEMS.TCB_Pointer |
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407 | ); |
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408 | @end example |
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409 | @end ifset |
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410 | |
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411 | where current_task can be used to access the TCB for |
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412 | the currently executing task which has begun. The distinction |
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413 | between the TASK_BEGIN and TASK_START extension is that the |
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414 | TASK_BEGIN extension is executed in the context of the actual |
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415 | task while the TASK_START extension is executed in the context |
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416 | of the task performing the task_start directive. For most |
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417 | extensions, this is not a critical distinction. |
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418 | |
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419 | @subsubsection TASK_EXITTED Extension |
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420 | |
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421 | The TASK_EXITTED extension is invoked when a task |
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422 | exits the body of the starting procedure by either an implicit |
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423 | or explicit return statement. This user extension have a |
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424 | prototype similar to the following: |
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425 | |
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426 | @findex rtems_task_exitted_extension |
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427 | @ifset is-C |
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428 | @example |
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429 | rtems_extension user_task_exitted( |
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430 | rtems_tcb *current_task |
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431 | ); |
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432 | @end example |
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433 | @end ifset |
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434 | |
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435 | @ifset is-Ada |
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436 | @example |
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437 | procedure User_Task_Exitted ( |
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438 | Current_Task : in RTEMS.TCB_Pointer |
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439 | ); |
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440 | @end example |
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441 | @end ifset |
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442 | |
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443 | where current_task can be used to access the TCB for |
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444 | the currently executing task which has just exitted. |
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445 | |
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446 | Although exiting of task is often considered to be a |
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447 | fatal error, this extension allows recovery by either restarting |
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448 | or deleting the exiting task. If the user does not wish to |
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449 | recover, then a fatal error may be reported. If the user does |
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450 | not provide a TASK_EXITTED extension or the provided handler |
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451 | returns control to RTEMS, then the RTEMS default handler will be |
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452 | used. This default handler invokes the directive |
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453 | fatal_error_occurred with the @code{@value{RPREFIX}TASK_EXITTED} directive status. |
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454 | |
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455 | @subsubsection FATAL Error Extension |
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456 | |
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457 | The FATAL error extension is associated with the |
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458 | fatal_error_occurred directive. If this extension is defined in |
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459 | any static or dynamic extension set and the fatal_error_occurred |
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460 | directive has been invoked, then this extension will be called. |
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461 | This extension should have a prototype similar to the following: |
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462 | |
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463 | @findex rtems_fatal_extension |
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464 | @ifset is-C |
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465 | @example |
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466 | rtems_extension user_fatal_error( |
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467 | Internal_errors_Source the_source, |
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468 | rtems_boolean is_internal, |
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469 | rtems_unsigned32 the_error |
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470 | ); |
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471 | @end example |
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472 | @end ifset |
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473 | |
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474 | @ifset is-Ada |
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475 | @example |
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476 | procedure User_Fatal_Error ( |
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477 | Error : in RTEMS.Unsigned32 |
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478 | ); |
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479 | @end example |
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480 | @end ifset |
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481 | |
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482 | where the_error is the error code passed to the |
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483 | fatal_error_occurred directive. This extension is invoked from |
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484 | the fatal_error_occurred directive. |
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485 | |
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486 | If defined, the user's FATAL error extension is |
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487 | invoked before RTEMS' default fatal error routine is invoked and |
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488 | the processor is stopped. For example, this extension could be |
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489 | used to pass control to a debugger when a fatal error occurs. |
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490 | This extension should not call any RTEMS directives. |
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491 | |
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492 | @subsection Order of Invocation |
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493 | |
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494 | When one of the critical system events occur, the |
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495 | user extensions are invoked in either "forward" or "reverse" |
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496 | order. Forward order indicates that the static extension set is |
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497 | invoked followed by the dynamic extension sets in the order in |
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498 | which they were created. Reverse order means that the dynamic |
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499 | extension sets are invoked in the opposite of the order in which |
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500 | they were created followed by the static extension set. By |
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501 | invoking the extension sets in this order, extensions can be |
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502 | built upon one another. At the following system events, the |
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503 | extensions are invoked in forward order: |
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504 | |
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505 | @itemize @bullet |
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506 | @item Task creation |
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507 | @item Task initiation |
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508 | @item Task reinitiation |
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509 | @item Task deletion |
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510 | @item Task context switch |
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511 | @item Post task context switch |
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512 | @item Task begins to execute |
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513 | @end itemize |
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514 | |
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515 | |
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516 | At the following system events, the extensions are |
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517 | invoked in reverse order: |
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518 | |
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519 | @itemize @bullet |
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520 | @item Task deletion |
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521 | @item Fatal error detection |
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522 | @end itemize |
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523 | |
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524 | At these system events, the extensions are invoked in |
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525 | reverse order to insure that if an extension set is built upon |
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526 | another, the more complicated extension is invoked before the |
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527 | extension set it is built upon. For example, by invoking the |
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528 | static extension set last it is known that the "system" fatal |
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529 | error extension will be the last fatal error extension executed. |
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530 | Another example is use of the task delete extension by the |
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531 | Standard C Library. Extension sets which are installed after |
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532 | the Standard C Library will operate correctly even if they |
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533 | utilize the C Library because the C Library's TASK_DELETE |
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534 | extension is invoked after that of the other extensions. |
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535 | |
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536 | @section Operations |
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537 | |
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538 | @subsection Creating an Extension Set |
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539 | |
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540 | The @code{@value{DIRPREFIX}extension_create} directive creates and installs |
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541 | an extension set by allocating a Extension Set Control Block |
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542 | (ESCB), assigning the extension set a user-specified name, and |
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543 | assigning it an extension set ID. Newly created extension sets |
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544 | are immediately installed and are invoked upon the next system |
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545 | even supporting an extension. |
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546 | |
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547 | @subsection Obtaining Extension Set IDs |
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548 | |
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549 | When an extension set is created, RTEMS generates a |
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550 | unique extension set ID and assigns it to the created extension |
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551 | set until it is deleted. The extension ID may be obtained by |
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552 | either of two methods. First, as the result of an invocation of |
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553 | the @code{@value{DIRPREFIX}extension_create} |
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554 | directive, the extension set ID is stored |
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555 | in a user provided location. Second, the extension set ID may |
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556 | be obtained later using the @code{@value{DIRPREFIX}extension_ident} |
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557 | directive. The extension set ID is used by other directives |
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558 | to manipulate this extension set. |
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559 | |
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560 | @subsection Deleting an Extension Set |
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561 | |
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562 | The @code{@value{DIRPREFIX}extension_delete} directive is used to delete an |
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563 | extension set. The extension set's control block is returned to |
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564 | the ESCB free list when it is deleted. An extension set can be |
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565 | deleted by a task other than the task which created the |
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566 | extension set. Any subsequent references to the extension's |
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567 | name and ID are invalid. |
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568 | |
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569 | @section Directives |
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570 | |
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571 | This section details the user extension manager's |
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572 | directives. A subsection is dedicated to each of this manager's |
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573 | directives and describes the calling sequence, related |
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574 | constants, usage, and status codes. |
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575 | |
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576 | @c |
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577 | @c |
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578 | @c |
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579 | @page |
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580 | @subsection EXTENSION_CREATE - Create a extension set |
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581 | |
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582 | @cindex create an extension set |
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583 | |
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584 | @subheading CALLING SEQUENCE: |
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585 | |
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586 | @ifset is-C |
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587 | @findex rtems_extension_create |
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588 | @example |
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589 | rtems_status_code rtems_extension_create( |
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590 | rtems_name name, |
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591 | rtems_extensions_table *table, |
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592 | rtems_id *id |
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593 | ); |
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594 | @end example |
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595 | @end ifset |
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596 | |
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597 | @ifset is-Ada |
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598 | @example |
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599 | procedure Extension_Create ( |
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600 | Name : in RTEMS.Name; |
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601 | Table : in RTEMS.Extensions_Table_Pointer; |
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602 | ID : out RTEMS.ID; |
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603 | Result : out RTEMS.Status_Codes |
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604 | ); |
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605 | @end example |
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606 | @end ifset |
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607 | |
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608 | @subheading DIRECTIVE STATUS CODES: |
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609 | @code{@value{RPREFIX}SUCCESSFUL} - extension set created successfully@* |
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610 | @code{@value{RPREFIX}INVALID_NAME} - invalid extension set name@* |
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611 | @code{@value{RPREFIX}TOO_MANY} - too many extension sets created |
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612 | |
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613 | @subheading DESCRIPTION: |
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614 | |
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615 | This directive creates a extension set. The assigned |
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616 | extension set id is returned in id. This id is used to access |
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617 | the extension set with other user extension manager directives. |
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618 | For control and maintenance of the extension set, RTEMS |
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619 | allocates an ESCB from the local ESCB free pool and initializes |
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620 | it. |
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621 | |
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622 | @subheading NOTES: |
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623 | |
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624 | This directive will not cause the calling task to be |
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625 | preempted. |
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626 | |
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627 | @c |
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628 | @c |
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629 | @c |
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630 | @page |
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631 | @subsection EXTENSION_IDENT - Get ID of a extension set |
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632 | |
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633 | @cindex get ID of an extension set |
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634 | @cindex obtain ID of an extension set |
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635 | |
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636 | @subheading CALLING SEQUENCE: |
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637 | |
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638 | @ifset is-C |
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639 | @findex rtems_extension_ident |
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640 | @example |
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641 | rtems_status_code rtems_extension_ident( |
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642 | rtems_name name, |
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643 | rtems_id *id |
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644 | ); |
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645 | @end example |
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646 | @end ifset |
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647 | |
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648 | @ifset is-Ada |
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649 | @example |
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650 | procedure Extension_Ident ( |
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651 | Name : in RTEMS.Name; |
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652 | ID : out RTEMS.ID; |
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653 | Result : out RTEMS.Status_Codes |
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654 | ); |
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655 | @end example |
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656 | @end ifset |
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657 | |
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658 | @subheading DIRECTIVE STATUS CODES: |
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659 | @code{@value{RPREFIX}SUCCESSFUL} - extension set identified successfully@* |
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660 | @code{@value{RPREFIX}INVALID_NAME} - extension set name not found |
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661 | |
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662 | @subheading DESCRIPTION: |
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663 | |
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664 | This directive obtains the extension set id |
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665 | associated with the extension set name to be acquired. If the |
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666 | extension set name is not unique, then the extension set id will |
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667 | match one of the extension sets with that name. However, this |
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668 | extension set id is not guaranteed to correspond to the desired |
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669 | extension set. The extension set id is used to access this |
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670 | extension set in other extension set related directives. |
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671 | |
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672 | @subheading NOTES: |
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673 | |
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674 | This directive will not cause the running task to be |
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675 | preempted. |
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676 | |
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677 | @c |
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678 | @c |
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679 | @c |
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680 | @page |
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681 | @subsection EXTENSION_DELETE - Delete a extension set |
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682 | |
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683 | @cindex delete an extension set |
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684 | |
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685 | @subheading CALLING SEQUENCE: |
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686 | |
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687 | @ifset is-C |
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688 | @findex rtems_extension_delete |
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689 | @example |
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690 | rtems_status_code rtems_extension_delete( |
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691 | rtems_id id |
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692 | ); |
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693 | @end example |
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694 | @end ifset |
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695 | |
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696 | @ifset is-Ada |
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697 | @example |
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698 | procedure Extension_Delete ( |
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699 | ID : in RTEMS.ID; |
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700 | Result : out RTEMS.Status_Codes |
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701 | ); |
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702 | @end example |
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703 | @end ifset |
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704 | |
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705 | @subheading DIRECTIVE STATUS CODES: |
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706 | @code{@value{RPREFIX}SUCCESSFUL} - extension set deleted successfully@* |
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707 | @code{@value{RPREFIX}INVALID_ID} - invalid extension set id |
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708 | |
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709 | @subheading DESCRIPTION: |
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710 | |
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711 | This directive deletes the extension set specified by |
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712 | id. If the extension set is running, it is automatically |
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713 | canceled. The ESCB for the deleted extension set is reclaimed |
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714 | by RTEMS. |
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715 | |
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716 | @subheading NOTES: |
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717 | |
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718 | This directive will not cause the running task to be |
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719 | preempted. |
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720 | |
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721 | A extension set can be deleted by a task other than |
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722 | the task which created the extension set. |
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723 | |
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724 | @subheading NOTES: |
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725 | |
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726 | This directive will not cause the running task to be |
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727 | preempted. |
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