1 | .. SPDX-License-Identifier: CC-BY-SA-4.0 |
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2 | |
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3 | .. Copyright (C) 2020, 2021 embedded brains GmbH (http://www.embedded-brains.de) |
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4 | .. Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR) |
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5 | |
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6 | .. This file is part of the RTEMS quality process and was automatically |
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7 | .. generated. If you find something that needs to be fixed or |
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8 | .. worded better please post a report or patch to an RTEMS mailing list |
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9 | .. or raise a bug report: |
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10 | .. |
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11 | .. https://www.rtems.org/bugs.html |
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12 | .. |
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13 | .. For information on updating and regenerating please refer to the How-To |
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14 | .. section in the Software Requirements Engineering chapter of the |
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15 | .. RTEMS Software Engineering manual. The manual is provided as a part of |
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16 | .. a release. For development sources please refer to the online |
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17 | .. documentation at: |
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18 | .. |
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19 | .. https://docs.rtems.org |
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20 | |
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21 | .. _MessageManagerDirectives: |
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22 | |
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23 | Directives |
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24 | ========== |
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25 | |
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26 | This section details the directives of the Message Manager. A subsection is |
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27 | dedicated to each of this manager's directives and lists the calling sequence, |
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28 | parameters, description, return values, and notes of the directive. |
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29 | |
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30 | .. Generated from spec:/rtems/message/if/create |
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31 | |
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32 | .. raw:: latex |
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33 | |
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34 | \clearpage |
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35 | |
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36 | .. index:: rtems_message_queue_create() |
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37 | .. index:: create a message queue |
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38 | |
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39 | .. _InterfaceRtemsMessageQueueCreate: |
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40 | |
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41 | rtems_message_queue_create() |
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42 | ---------------------------- |
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43 | |
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44 | Creates a message queue. |
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45 | |
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46 | .. rubric:: CALLING SEQUENCE: |
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47 | |
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48 | .. code-block:: c |
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49 | |
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50 | rtems_status_code rtems_message_queue_create( |
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51 | rtems_name name, |
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52 | uint32_t count, |
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53 | size_t max_message_size, |
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54 | rtems_attribute attribute_set, |
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55 | rtems_id *id |
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56 | ); |
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57 | |
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58 | .. rubric:: PARAMETERS: |
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59 | |
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60 | ``name`` |
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61 | This parameter is the object name of the message queue. |
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62 | |
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63 | ``count`` |
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64 | This parameter is the maximum count of pending messages supported by the |
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65 | message queue. |
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66 | |
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67 | ``max_message_size`` |
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68 | This parameter is the maximum size in bytes of a message supported by the |
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69 | message queue. |
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70 | |
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71 | ``attribute_set`` |
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72 | This parameter is the attribute set of the message queue. |
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73 | |
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74 | ``id`` |
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75 | This parameter is the pointer to an :c:type:`rtems_id` object. When the |
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76 | directive call is successful, the identifier of the created message queue |
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77 | will be stored in this object. |
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78 | |
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79 | .. rubric:: DESCRIPTION: |
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80 | |
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81 | This directive creates a message queue which resides on the local node. The |
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82 | message queue has the user-defined object name specified in ``name``. Memory |
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83 | is allocated from the RTEMS Workspace for the count of messages specified in |
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84 | ``count``, each of ``max_message_size`` bytes in length. The assigned object |
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85 | identifier is returned in ``id``. This identifier is used to access the |
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86 | message queue with other message queue related directives. |
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87 | |
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88 | The **attribute set** specified in ``attribute_set`` is built through a |
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89 | *bitwise or* of the attribute constants described below. Not all combinations |
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90 | of attributes are allowed. Some attributes are mutually exclusive. If |
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91 | mutually exclusive attributes are combined, the behaviour is undefined. |
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92 | Attributes not mentioned below are not evaluated by this directive and have no |
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93 | effect. Default attributes can be selected by using the |
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94 | :c:macro:`RTEMS_DEFAULT_ATTRIBUTES` constant. The attribute set defines |
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95 | |
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96 | * the scope of the message queue: :c:macro:`RTEMS_LOCAL` (default) or |
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97 | :c:macro:`RTEMS_GLOBAL` and |
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98 | |
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99 | * the task wait queue discipline used by the message queue: |
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100 | :c:macro:`RTEMS_FIFO` (default) or :c:macro:`RTEMS_PRIORITY`. |
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101 | |
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102 | The message queue has a local or global **scope** in a multiprocessing network |
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103 | (this attribute does not refer to SMP systems). The scope is selected by the |
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104 | mutually exclusive :c:macro:`RTEMS_LOCAL` and :c:macro:`RTEMS_GLOBAL` |
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105 | attributes. |
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106 | |
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107 | * A **local scope** is the default and can be emphasized through the use of the |
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108 | :c:macro:`RTEMS_LOCAL` attribute. A local message queue can be only used by |
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109 | the node which created it. |
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110 | |
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111 | * A **global scope** is established if the :c:macro:`RTEMS_GLOBAL` attribute is |
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112 | set. Setting the global attribute in a single node system has no effect. |
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113 | |
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114 | The **task wait queue discipline** is selected by the mutually exclusive |
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115 | :c:macro:`RTEMS_FIFO` and :c:macro:`RTEMS_PRIORITY` attributes. The discipline |
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116 | defines the order in which tasks wait for a message to receive on a currently |
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117 | empty message queue. |
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118 | |
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119 | * The **FIFO discipline** is the default and can be emphasized through use of |
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120 | the :c:macro:`RTEMS_FIFO` attribute. |
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121 | |
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122 | * The **priority discipline** is selected by the :c:macro:`RTEMS_PRIORITY` |
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123 | attribute. |
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124 | |
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125 | .. rubric:: RETURN VALUES: |
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126 | |
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127 | :c:macro:`RTEMS_SUCCESSFUL` |
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128 | The requested operation was successful. |
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129 | |
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130 | :c:macro:`RTEMS_INVALID_NAME` |
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131 | The ``name`` parameter was invalid. |
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132 | |
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133 | :c:macro:`RTEMS_INVALID_ADDRESS` |
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134 | The ``id`` parameter was `NULL |
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135 | <https://en.cppreference.com/w/c/types/NULL>`_. |
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136 | |
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137 | :c:macro:`RTEMS_INVALID_NUMBER` |
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138 | The ``count`` parameter was invalid. |
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139 | |
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140 | :c:macro:`RTEMS_INVALID_SIZE` |
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141 | The ``max_message_size`` parameter was invalid. |
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142 | |
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143 | :c:macro:`RTEMS_TOO_MANY` |
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144 | There was no inactive object available to create a message queue. The |
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145 | number of message queue available to the application is configured through |
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146 | the :ref:`CONFIGURE_MAXIMUM_MESSAGE_QUEUES` application configuration |
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147 | option. |
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148 | |
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149 | :c:macro:`RTEMS_TOO_MANY` |
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150 | In multiprocessing configurations, there was no inactive global object |
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151 | available to create a global message queue. The number of global objects |
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152 | available to the application is configured through the |
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153 | :ref:`CONFIGURE_MP_MAXIMUM_GLOBAL_OBJECTS` application configuration |
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154 | option. |
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155 | |
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156 | :c:macro:`RTEMS_INVALID_NUMBER` |
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157 | The product of ``count`` and ``max_message_size`` is greater than the |
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158 | maximum storage size. |
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159 | |
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160 | :c:macro:`RTEMS_UNSATISFIED` |
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161 | There was not enough memory available in the RTEMS Workspace to allocate |
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162 | the message buffers for the message queue. |
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163 | |
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164 | .. rubric:: NOTES: |
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165 | |
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166 | For message queues with a global scope, the maximum message size is effectively |
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167 | limited to the longest message which the :term:`MPCI` is capable of |
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168 | transmitting. |
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169 | |
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170 | For control and maintenance of the message queue, RTEMS allocates a :term:`QCB` |
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171 | from the local QCB free pool and initializes it. |
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172 | |
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173 | The QCB for a global message queue is allocated on the local node. Message |
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174 | queues should not be made global unless remote tasks must interact with the |
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175 | message queue. This is to avoid the system overhead incurred by the creation |
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176 | of a global message queue. When a global message queue is created, the message |
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177 | queue's name and identifier must be transmitted to every node in the system for |
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178 | insertion in the local copy of the global object table. |
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179 | |
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180 | .. rubric:: CONSTRAINTS: |
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181 | |
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182 | The following constraints apply to this directive: |
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183 | |
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184 | * The directive may be called from within device driver initialization context. |
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185 | |
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186 | * The directive may be called from within task context. |
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187 | |
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188 | * The directive may obtain and release the object allocator mutex. This may |
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189 | cause the calling task to be preempted. |
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190 | |
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191 | * When the directive operates on a global object, the directive sends a message |
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192 | to remote nodes. This may preempt the calling task. |
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193 | |
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194 | * The number of message queues available to the application is configured |
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195 | through the :ref:`CONFIGURE_MAXIMUM_MESSAGE_QUEUES` application configuration |
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196 | option. |
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197 | |
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198 | * Where the object class corresponding to the directive is configured to use |
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199 | unlimited objects, the directive may allocate memory from the RTEMS |
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200 | Workspace. |
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201 | |
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202 | * The number of global objects available to the application is configured |
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203 | through the :ref:`CONFIGURE_MP_MAXIMUM_GLOBAL_OBJECTS` application |
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204 | configuration option. |
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205 | |
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206 | .. Generated from spec:/rtems/message/if/construct |
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207 | |
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208 | .. raw:: latex |
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209 | |
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210 | \clearpage |
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211 | |
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212 | .. index:: rtems_message_queue_construct() |
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213 | |
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214 | .. _InterfaceRtemsMessageQueueConstruct: |
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215 | |
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216 | rtems_message_queue_construct() |
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217 | ------------------------------- |
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218 | |
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219 | Constructs a message queue from the specified the message queue configuration. |
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220 | |
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221 | .. rubric:: CALLING SEQUENCE: |
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222 | |
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223 | .. code-block:: c |
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224 | |
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225 | rtems_status_code rtems_message_queue_construct( |
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226 | const rtems_message_queue_config *config, |
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227 | rtems_id *id |
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228 | ); |
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229 | |
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230 | .. rubric:: PARAMETERS: |
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231 | |
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232 | ``config`` |
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233 | This parameter is the message queue configuration. |
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234 | |
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235 | ``id`` |
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236 | This parameter is the pointer to an :c:type:`rtems_id` object. When the |
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237 | directive call is successful, the identifier of the constructed message |
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238 | queue will be stored in this object. |
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239 | |
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240 | .. rubric:: RETURN VALUES: |
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241 | |
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242 | :c:macro:`RTEMS_SUCCESSFUL` |
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243 | The requested operation was successful. |
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244 | |
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245 | :c:macro:`RTEMS_INVALID_ADDRESS` |
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246 | The ``config`` parameter was `NULL |
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247 | <https://en.cppreference.com/w/c/types/NULL>`_. |
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248 | |
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249 | :c:macro:`RTEMS_INVALID_NAME` |
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250 | The message queue name in the configuration was invalid. |
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251 | |
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252 | :c:macro:`RTEMS_INVALID_ADDRESS` |
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253 | The ``id`` parameter was `NULL |
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254 | <https://en.cppreference.com/w/c/types/NULL>`_. |
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255 | |
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256 | :c:macro:`RTEMS_INVALID_NUMBER` |
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257 | The maximum number of pending messages in the configuration was zero. |
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258 | |
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259 | :c:macro:`RTEMS_INVALID_SIZE` |
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260 | The maximum message size in the configuration was zero. |
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261 | |
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262 | :c:macro:`RTEMS_TOO_MANY` |
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263 | There was no inactive message queue object available to construct a message |
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264 | queue. |
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265 | |
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266 | :c:macro:`RTEMS_TOO_MANY` |
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267 | In multiprocessing configurations, there was no inactive global object |
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268 | available to construct a global message queue. |
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269 | |
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270 | :c:macro:`RTEMS_INVALID_SIZE` |
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271 | The maximum message size in the configuration was too big and resulted in |
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272 | integer overflows in calculations carried out to determine the size of the |
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273 | message buffer area. |
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274 | |
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275 | :c:macro:`RTEMS_INVALID_NUMBER` |
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276 | The maximum number of pending messages in the configuration was too big and |
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277 | resulted in integer overflows in calculations carried out to determine the |
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278 | size of the message buffer area. |
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279 | |
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280 | :c:macro:`RTEMS_UNSATISFIED` |
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281 | The message queue storage area begin pointer in the configuration was `NULL |
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282 | <https://en.cppreference.com/w/c/types/NULL>`_. |
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283 | |
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284 | :c:macro:`RTEMS_UNSATISFIED` |
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285 | The message queue storage area size in the configuration was not equal to |
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286 | the size calculated from the maximum number of pending messages and the |
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287 | maximum message size. |
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288 | |
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289 | .. rubric:: NOTES: |
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290 | |
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291 | In contrast to message queues created by |
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292 | :ref:`InterfaceRtemsMessageQueueCreate`, the message queues constructed by this |
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293 | directive use a user-provided message buffer storage area. |
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294 | |
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295 | This directive is intended for applications which do not want to use the RTEMS |
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296 | Workspace and instead statically allocate all operating system resources. An |
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297 | application based solely on static allocation can avoid any runtime memory |
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298 | allocators. This can simplify the application architecture as well as any |
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299 | analysis that may be required. |
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300 | |
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301 | The value for :ref:`CONFIGURE_MESSAGE_BUFFER_MEMORY` should not include memory |
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302 | for message queues constructed by :ref:`InterfaceRtemsMessageQueueConstruct`. |
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303 | |
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304 | .. rubric:: CONSTRAINTS: |
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305 | |
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306 | The following constraints apply to this directive: |
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307 | |
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308 | * The directive may be called from within device driver initialization context. |
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309 | |
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310 | * The directive may be called from within task context. |
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311 | |
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312 | * The directive may obtain and release the object allocator mutex. This may |
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313 | cause the calling task to be preempted. |
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314 | |
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315 | * When the directive operates on a global object, the directive sends a message |
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316 | to remote nodes. This may preempt the calling task. |
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317 | |
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318 | * The number of message queues available to the application is configured |
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319 | through the :ref:`CONFIGURE_MAXIMUM_MESSAGE_QUEUES` application configuration |
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320 | option. |
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321 | |
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322 | * Where the object class corresponding to the directive is configured to use |
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323 | unlimited objects, the directive may allocate memory from the RTEMS |
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324 | Workspace. |
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325 | |
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326 | * The number of global objects available to the application is configured |
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327 | through the :ref:`CONFIGURE_MP_MAXIMUM_GLOBAL_OBJECTS` application |
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328 | configuration option. |
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329 | |
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330 | .. Generated from spec:/rtems/message/if/ident |
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331 | |
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332 | .. raw:: latex |
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333 | |
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334 | \clearpage |
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335 | |
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336 | .. index:: rtems_message_queue_ident() |
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337 | |
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338 | .. _InterfaceRtemsMessageQueueIdent: |
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339 | |
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340 | rtems_message_queue_ident() |
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341 | --------------------------- |
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342 | |
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343 | Identifies a message queue by the object name. |
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344 | |
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345 | .. rubric:: CALLING SEQUENCE: |
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346 | |
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347 | .. code-block:: c |
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348 | |
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349 | rtems_status_code rtems_message_queue_ident( |
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350 | rtems_name name, |
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351 | uint32_t node, |
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352 | rtems_id *id |
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353 | ); |
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354 | |
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355 | .. rubric:: PARAMETERS: |
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356 | |
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357 | ``name`` |
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358 | This parameter is the object name to look up. |
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359 | |
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360 | ``node`` |
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361 | This parameter is the node or node set to search for a matching object. |
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362 | |
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363 | ``id`` |
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364 | This parameter is the pointer to an :c:type:`rtems_id` object. When the |
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365 | directive call is successful, the object identifier of an object with the |
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366 | specified name will be stored in this object. |
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367 | |
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368 | .. rubric:: DESCRIPTION: |
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369 | |
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370 | This directive obtains a message queue identifier associated with the message |
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371 | queue name specified in ``name``. |
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372 | |
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373 | The node to search is specified in ``node``. It shall be |
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374 | |
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375 | * a valid node number, |
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376 | |
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377 | * the constant :c:macro:`RTEMS_SEARCH_ALL_NODES` to search in all nodes, |
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378 | |
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379 | * the constant :c:macro:`RTEMS_SEARCH_LOCAL_NODE` to search in the local node |
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380 | only, or |
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381 | |
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382 | * the constant :c:macro:`RTEMS_SEARCH_OTHER_NODES` to search in all nodes |
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383 | except the local node. |
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384 | |
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385 | .. rubric:: RETURN VALUES: |
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386 | |
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387 | :c:macro:`RTEMS_SUCCESSFUL` |
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388 | The requested operation was successful. |
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389 | |
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390 | :c:macro:`RTEMS_INVALID_ADDRESS` |
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391 | The ``id`` parameter was `NULL |
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392 | <https://en.cppreference.com/w/c/types/NULL>`_. |
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393 | |
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394 | :c:macro:`RTEMS_INVALID_NAME` |
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395 | The ``name`` parameter was 0. |
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396 | |
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397 | :c:macro:`RTEMS_INVALID_NAME` |
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398 | There was no object with the specified name on the specified nodes. |
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399 | |
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400 | :c:macro:`RTEMS_INVALID_NODE` |
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401 | In multiprocessing configurations, the specified node was invalid. |
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402 | |
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403 | .. rubric:: NOTES: |
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404 | |
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405 | If the message queue name is not unique, then the message queue identifier will |
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406 | match the first message queue with that name in the search order. However, this |
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407 | message queue identifier is not guaranteed to correspond to the desired message |
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408 | queue. |
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409 | |
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410 | The objects are searched from lowest to the highest index. If ``node`` is |
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411 | :c:macro:`RTEMS_SEARCH_ALL_NODES`, all nodes are searched with the local node |
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412 | being searched first. All other nodes are searched from lowest to the highest |
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413 | node number. |
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414 | |
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415 | If node is a valid node number which does not represent the local node, then |
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416 | only the message queues exported by the designated node are searched. |
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417 | |
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418 | This directive does not generate activity on remote nodes. It accesses only |
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419 | the local copy of the global object table. |
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420 | |
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421 | The message queue identifier is used with other message related directives to |
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422 | access the message queue. |
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423 | |
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424 | .. rubric:: CONSTRAINTS: |
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425 | |
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426 | The following constraints apply to this directive: |
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427 | |
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428 | * The directive may be called from within any runtime context. |
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429 | |
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430 | * The directive will not cause the calling task to be preempted. |
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431 | |
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432 | .. Generated from spec:/rtems/message/if/delete |
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433 | |
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434 | .. raw:: latex |
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435 | |
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436 | \clearpage |
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437 | |
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438 | .. index:: rtems_message_queue_delete() |
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439 | .. index:: delete a message queue |
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440 | |
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441 | .. _InterfaceRtemsMessageQueueDelete: |
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442 | |
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443 | rtems_message_queue_delete() |
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444 | ---------------------------- |
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445 | |
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446 | Deletes the message queue. |
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447 | |
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448 | .. rubric:: CALLING SEQUENCE: |
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449 | |
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450 | .. code-block:: c |
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451 | |
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452 | rtems_status_code rtems_message_queue_delete( rtems_id id ); |
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453 | |
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454 | .. rubric:: PARAMETERS: |
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455 | |
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456 | ``id`` |
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457 | This parameter is the message queue identifier. |
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458 | |
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459 | .. rubric:: DESCRIPTION: |
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460 | |
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461 | This directive deletes the message queue specified by ``id``. As a result of |
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462 | this directive, all tasks blocked waiting to receive a message from this queue |
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463 | will be readied and returned a status code which indicates that the message |
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464 | queue was deleted. |
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465 | |
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466 | .. rubric:: RETURN VALUES: |
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467 | |
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468 | :c:macro:`RTEMS_SUCCESSFUL` |
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469 | The requested operation was successful. |
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470 | |
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471 | :c:macro:`RTEMS_INVALID_ID` |
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472 | There was no message queue associated with the identifier specified by |
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473 | ``id``. |
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474 | |
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475 | :c:macro:`RTEMS_ILLEGAL_ON_REMOTE_OBJECT` |
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476 | The message queue resided on a remote node. |
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477 | |
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478 | .. rubric:: NOTES: |
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479 | |
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480 | When the message queue is deleted, any messages in the queue are returned to |
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481 | the free message buffer pool. Any information stored in those messages is |
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482 | lost. The message buffers allocated for the message queue are reclaimed. |
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483 | |
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484 | The :term:`QCB` for the deleted message queue is reclaimed by RTEMS. |
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485 | |
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486 | When a global message queue is deleted, the message queue identifier must be |
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487 | transmitted to every node in the system for deletion from the local copy of the |
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488 | global object table. |
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489 | |
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490 | The message queue must reside on the local node, even if the message queue was |
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491 | created with the :c:macro:`RTEMS_GLOBAL` attribute. |
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492 | |
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493 | Proxies, used to represent remote tasks, are reclaimed when the message queue |
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494 | is deleted. |
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495 | |
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496 | .. rubric:: CONSTRAINTS: |
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497 | |
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498 | The following constraints apply to this directive: |
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499 | |
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500 | * The directive may be called from within device driver initialization context. |
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501 | |
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502 | * The directive may be called from within task context. |
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503 | |
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504 | * The directive may obtain and release the object allocator mutex. This may |
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505 | cause the calling task to be preempted. |
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506 | |
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507 | * When the directive operates on a global object, the directive sends a message |
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508 | to remote nodes. This may preempt the calling task. |
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509 | |
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510 | * The calling task does not have to be the task that created the object. Any |
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511 | local task that knows the object identifier can delete the object. |
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512 | |
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513 | * Where the object class corresponding to the directive is configured to use |
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514 | unlimited objects, the directive may free memory to the RTEMS Workspace. |
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515 | |
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516 | .. Generated from spec:/rtems/message/if/send |
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517 | |
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518 | .. raw:: latex |
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519 | |
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520 | \clearpage |
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521 | |
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522 | .. index:: rtems_message_queue_send() |
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523 | .. index:: send message to a queue |
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524 | |
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525 | .. _InterfaceRtemsMessageQueueSend: |
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526 | |
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527 | rtems_message_queue_send() |
---|
528 | -------------------------- |
---|
529 | |
---|
530 | Puts the message at the rear of the queue. |
---|
531 | |
---|
532 | .. rubric:: CALLING SEQUENCE: |
---|
533 | |
---|
534 | .. code-block:: c |
---|
535 | |
---|
536 | rtems_status_code rtems_message_queue_send( |
---|
537 | rtems_id id, |
---|
538 | const void *buffer, |
---|
539 | size_t size |
---|
540 | ); |
---|
541 | |
---|
542 | .. rubric:: PARAMETERS: |
---|
543 | |
---|
544 | ``id`` |
---|
545 | This parameter is the queue identifier. |
---|
546 | |
---|
547 | ``buffer`` |
---|
548 | This parameter is the begin address of the message buffer to send. |
---|
549 | |
---|
550 | ``size`` |
---|
551 | This parameter is the size in bytes of the message buffer to send. |
---|
552 | |
---|
553 | .. rubric:: DESCRIPTION: |
---|
554 | |
---|
555 | This directive sends the message ``buffer`` of ``size`` bytes in length to the |
---|
556 | queue specified by ``id``. If a task is waiting at the queue, then the message |
---|
557 | is copied to the waiting task's buffer and the task is unblocked. If no tasks |
---|
558 | are waiting at the queue, then the message is copied to a message buffer which |
---|
559 | is obtained from this message queue's message buffer pool. The message buffer |
---|
560 | is then placed at the rear of the queue. |
---|
561 | |
---|
562 | .. rubric:: RETURN VALUES: |
---|
563 | |
---|
564 | :c:macro:`RTEMS_SUCCESSFUL` |
---|
565 | The requested operation was successful. |
---|
566 | |
---|
567 | :c:macro:`RTEMS_INVALID_ID` |
---|
568 | There was no queue associated with the identifier specified by ``id``. |
---|
569 | |
---|
570 | :c:macro:`RTEMS_INVALID_ADDRESS` |
---|
571 | The ``buffer`` parameter was `NULL |
---|
572 | <https://en.cppreference.com/w/c/types/NULL>`_. |
---|
573 | |
---|
574 | :c:macro:`RTEMS_INVALID_SIZE` |
---|
575 | The size of the message exceeded the maximum message size of the queue as |
---|
576 | defined by :ref:`InterfaceRtemsMessageQueueCreate` or |
---|
577 | :ref:`InterfaceRtemsMessageQueueConstruct`. |
---|
578 | |
---|
579 | :c:macro:`RTEMS_TOO_MANY` |
---|
580 | The maximum number of pending messages supported by the queue as defined by |
---|
581 | :ref:`InterfaceRtemsMessageQueueCreate` or |
---|
582 | :ref:`InterfaceRtemsMessageQueueConstruct` has been reached. |
---|
583 | |
---|
584 | .. rubric:: CONSTRAINTS: |
---|
585 | |
---|
586 | The following constraints apply to this directive: |
---|
587 | |
---|
588 | * The directive may be called from within task context. |
---|
589 | |
---|
590 | * The directive may be called from within interrupt context. |
---|
591 | |
---|
592 | * The directive may unblock a task. This may cause the calling task to be |
---|
593 | preempted. |
---|
594 | |
---|
595 | * When the directive operates on a remote object, the directive sends a message |
---|
596 | to the remote node and waits for a reply. This will preempt the calling |
---|
597 | task. |
---|
598 | |
---|
599 | .. Generated from spec:/rtems/message/if/urgent |
---|
600 | |
---|
601 | .. raw:: latex |
---|
602 | |
---|
603 | \clearpage |
---|
604 | |
---|
605 | .. index:: rtems_message_queue_urgent() |
---|
606 | .. index:: put message at front of queue |
---|
607 | |
---|
608 | .. _InterfaceRtemsMessageQueueUrgent: |
---|
609 | |
---|
610 | rtems_message_queue_urgent() |
---|
611 | ---------------------------- |
---|
612 | |
---|
613 | Puts the message at the front of the queue. |
---|
614 | |
---|
615 | .. rubric:: CALLING SEQUENCE: |
---|
616 | |
---|
617 | .. code-block:: c |
---|
618 | |
---|
619 | rtems_status_code rtems_message_queue_urgent( |
---|
620 | rtems_id id, |
---|
621 | const void *buffer, |
---|
622 | size_t size |
---|
623 | ); |
---|
624 | |
---|
625 | .. rubric:: PARAMETERS: |
---|
626 | |
---|
627 | ``id`` |
---|
628 | This parameter is the queue identifier. |
---|
629 | |
---|
630 | ``buffer`` |
---|
631 | This parameter is the begin address of the message buffer to send urgently. |
---|
632 | |
---|
633 | ``size`` |
---|
634 | This parameter is the size in bytes of the message buffer to send urgently. |
---|
635 | |
---|
636 | .. rubric:: DESCRIPTION: |
---|
637 | |
---|
638 | This directive sends the message ``buffer`` of ``size`` bytes in length to the |
---|
639 | queue specified by ``id``. If a task is waiting at the queue, then the message |
---|
640 | is copied to the waiting task's buffer and the task is unblocked. If no tasks |
---|
641 | are waiting at the queue, then the message is copied to a message buffer which |
---|
642 | is obtained from this message queue's message buffer pool. The message buffer |
---|
643 | is then placed at the front of the queue. |
---|
644 | |
---|
645 | .. rubric:: RETURN VALUES: |
---|
646 | |
---|
647 | :c:macro:`RTEMS_SUCCESSFUL` |
---|
648 | The requested operation was successful. |
---|
649 | |
---|
650 | :c:macro:`RTEMS_INVALID_ID` |
---|
651 | There was no queue associated with the identifier specified by ``id``. |
---|
652 | |
---|
653 | :c:macro:`RTEMS_INVALID_ADDRESS` |
---|
654 | The ``buffer`` parameter was `NULL |
---|
655 | <https://en.cppreference.com/w/c/types/NULL>`_. |
---|
656 | |
---|
657 | :c:macro:`RTEMS_INVALID_SIZE` |
---|
658 | The size of the message exceeded the maximum message size of the queue as |
---|
659 | defined by :ref:`InterfaceRtemsMessageQueueCreate` or |
---|
660 | :ref:`InterfaceRtemsMessageQueueConstruct`. |
---|
661 | |
---|
662 | :c:macro:`RTEMS_TOO_MANY` |
---|
663 | The maximum number of pending messages supported by the queue as defined by |
---|
664 | :ref:`InterfaceRtemsMessageQueueCreate` or |
---|
665 | :ref:`InterfaceRtemsMessageQueueConstruct` has been reached. |
---|
666 | |
---|
667 | .. rubric:: CONSTRAINTS: |
---|
668 | |
---|
669 | The following constraints apply to this directive: |
---|
670 | |
---|
671 | * The directive may be called from within task context. |
---|
672 | |
---|
673 | * The directive may be called from within interrupt context. |
---|
674 | |
---|
675 | * The directive may unblock a task. This may cause the calling task to be |
---|
676 | preempted. |
---|
677 | |
---|
678 | * When the directive operates on a remote object, the directive sends a message |
---|
679 | to the remote node and waits for a reply. This will preempt the calling |
---|
680 | task. |
---|
681 | |
---|
682 | .. Generated from spec:/rtems/message/if/broadcast |
---|
683 | |
---|
684 | .. raw:: latex |
---|
685 | |
---|
686 | \clearpage |
---|
687 | |
---|
688 | .. index:: rtems_message_queue_broadcast() |
---|
689 | .. index:: broadcast message to a queue |
---|
690 | |
---|
691 | .. _InterfaceRtemsMessageQueueBroadcast: |
---|
692 | |
---|
693 | rtems_message_queue_broadcast() |
---|
694 | ------------------------------- |
---|
695 | |
---|
696 | Broadcasts the messages to the tasks waiting at the queue. |
---|
697 | |
---|
698 | .. rubric:: CALLING SEQUENCE: |
---|
699 | |
---|
700 | .. code-block:: c |
---|
701 | |
---|
702 | rtems_status_code rtems_message_queue_broadcast( |
---|
703 | rtems_id id, |
---|
704 | const void *buffer, |
---|
705 | size_t size, |
---|
706 | uint32_t *count |
---|
707 | ); |
---|
708 | |
---|
709 | .. rubric:: PARAMETERS: |
---|
710 | |
---|
711 | ``id`` |
---|
712 | This parameter is the queue identifier. |
---|
713 | |
---|
714 | ``buffer`` |
---|
715 | This parameter is the begin address of the message buffer to broadcast. |
---|
716 | |
---|
717 | ``size`` |
---|
718 | This parameter is the size in bytes of the message buffer to broadcast. |
---|
719 | |
---|
720 | ``count`` |
---|
721 | This parameter is the pointer to an `uint32_t |
---|
722 | <https://en.cppreference.com/w/c/types/integer>`_ object. When the |
---|
723 | directive call is successful, the number of unblocked tasks will be stored |
---|
724 | in this object. |
---|
725 | |
---|
726 | .. rubric:: DESCRIPTION: |
---|
727 | |
---|
728 | This directive causes all tasks that are waiting at the queue specified by |
---|
729 | ``id`` to be unblocked and sent the message contained in ``buffer``. Before a |
---|
730 | task is unblocked, the message ``buffer`` of ``size`` byes in length is copied |
---|
731 | to that task's message buffer. The number of tasks that were unblocked is |
---|
732 | returned in ``count``. |
---|
733 | |
---|
734 | .. rubric:: RETURN VALUES: |
---|
735 | |
---|
736 | :c:macro:`RTEMS_SUCCESSFUL` |
---|
737 | The requested operation was successful. |
---|
738 | |
---|
739 | :c:macro:`RTEMS_INVALID_ID` |
---|
740 | There was no queue associated with the identifier specified by ``id``. |
---|
741 | |
---|
742 | :c:macro:`RTEMS_INVALID_ADDRESS` |
---|
743 | The ``buffer`` parameter was `NULL |
---|
744 | <https://en.cppreference.com/w/c/types/NULL>`_. |
---|
745 | |
---|
746 | :c:macro:`RTEMS_INVALID_ADDRESS` |
---|
747 | The ``count`` parameter was `NULL |
---|
748 | <https://en.cppreference.com/w/c/types/NULL>`_. |
---|
749 | |
---|
750 | :c:macro:`RTEMS_INVALID_SIZE` |
---|
751 | The size of the message exceeded the maximum message size of the queue as |
---|
752 | defined by :ref:`InterfaceRtemsMessageQueueCreate` or |
---|
753 | :ref:`InterfaceRtemsMessageQueueConstruct`. |
---|
754 | |
---|
755 | .. rubric:: NOTES: |
---|
756 | |
---|
757 | The execution time of this directive is directly related to the number of tasks |
---|
758 | waiting on the message queue, although it is more efficient than the equivalent |
---|
759 | number of invocations of :ref:`InterfaceRtemsMessageQueueSend`. |
---|
760 | |
---|
761 | .. rubric:: CONSTRAINTS: |
---|
762 | |
---|
763 | The following constraints apply to this directive: |
---|
764 | |
---|
765 | * The directive may be called from within task context. |
---|
766 | |
---|
767 | * The directive may be called from within interrupt context. |
---|
768 | |
---|
769 | * The directive may unblock a task. This may cause the calling task to be |
---|
770 | preempted. |
---|
771 | |
---|
772 | * When the directive operates on a remote object, the directive sends a message |
---|
773 | to the remote node and waits for a reply. This will preempt the calling |
---|
774 | task. |
---|
775 | |
---|
776 | .. Generated from spec:/rtems/message/if/receive |
---|
777 | |
---|
778 | .. raw:: latex |
---|
779 | |
---|
780 | \clearpage |
---|
781 | |
---|
782 | .. index:: rtems_message_queue_receive() |
---|
783 | .. index:: receive message from a queue |
---|
784 | |
---|
785 | .. _InterfaceRtemsMessageQueueReceive: |
---|
786 | |
---|
787 | rtems_message_queue_receive() |
---|
788 | ----------------------------- |
---|
789 | |
---|
790 | Receives a message from the queue. |
---|
791 | |
---|
792 | .. rubric:: CALLING SEQUENCE: |
---|
793 | |
---|
794 | .. code-block:: c |
---|
795 | |
---|
796 | rtems_status_code rtems_message_queue_receive( |
---|
797 | rtems_id id, |
---|
798 | void *buffer, |
---|
799 | size_t *size, |
---|
800 | rtems_option option_set, |
---|
801 | rtems_interval timeout |
---|
802 | ); |
---|
803 | |
---|
804 | .. rubric:: PARAMETERS: |
---|
805 | |
---|
806 | ``id`` |
---|
807 | This parameter is the queue identifier. |
---|
808 | |
---|
809 | ``buffer`` |
---|
810 | This parameter is the begin address of the buffer to receive the message. |
---|
811 | The buffer shall be large enough to receive a message of the maximum length |
---|
812 | of the queue as defined by :ref:`InterfaceRtemsMessageQueueCreate` or |
---|
813 | :ref:`InterfaceRtemsMessageQueueConstruct`. The ``size`` parameter cannot |
---|
814 | be used to specify the size of the buffer. |
---|
815 | |
---|
816 | ``size`` |
---|
817 | This parameter is the pointer to a `size_t |
---|
818 | <https://en.cppreference.com/w/c/types/size_t>`_ object. When the |
---|
819 | directive call is successful, the size in bytes of the received messages |
---|
820 | will be stored in this object. This parameter cannot be used to specify |
---|
821 | the size of the buffer. |
---|
822 | |
---|
823 | ``option_set`` |
---|
824 | This parameter is the option set. |
---|
825 | |
---|
826 | ``timeout`` |
---|
827 | This parameter is the timeout in :term:`clock ticks <clock tick>` if the |
---|
828 | :c:macro:`RTEMS_WAIT` option is set. Use :c:macro:`RTEMS_NO_TIMEOUT` to |
---|
829 | wait potentially forever. |
---|
830 | |
---|
831 | .. rubric:: DESCRIPTION: |
---|
832 | |
---|
833 | This directive receives a message from the queue specified by ``id``. |
---|
834 | |
---|
835 | The **option set** specified in ``option_set`` is built through a *bitwise or* |
---|
836 | of the option constants described below. Not all combinations of options are |
---|
837 | allowed. Some options are mutually exclusive. If mutually exclusive options |
---|
838 | are combined, the behaviour is undefined. Options not mentioned below are not |
---|
839 | evaluated by this directive and have no effect. Default options can be selected |
---|
840 | by using the :c:macro:`RTEMS_DEFAULT_OPTIONS` constant. |
---|
841 | |
---|
842 | The calling task can **wait** or **try to receive** a message from the queue |
---|
843 | according to the mutually exclusive :c:macro:`RTEMS_WAIT` and |
---|
844 | :c:macro:`RTEMS_NO_WAIT` options. |
---|
845 | |
---|
846 | * **Waiting to receive** a message from the queue is the default and can be |
---|
847 | emphasized through the use of the :c:macro:`RTEMS_WAIT` option. The |
---|
848 | ``timeout`` parameter defines how long the calling task is willing to wait. |
---|
849 | Use :c:macro:`RTEMS_NO_TIMEOUT` to wait potentially forever, otherwise set a |
---|
850 | timeout interval in clock ticks. |
---|
851 | |
---|
852 | * **Trying to receive** a message from the queue is selected by the |
---|
853 | :c:macro:`RTEMS_NO_WAIT` option. If this option is defined, then the |
---|
854 | ``timeout`` parameter is ignored. When a message from the queue cannot be |
---|
855 | immediately received, then the :c:macro:`RTEMS_UNSATISFIED` status is |
---|
856 | returned. |
---|
857 | |
---|
858 | With either :c:macro:`RTEMS_WAIT` or :c:macro:`RTEMS_NO_WAIT` if there is at |
---|
859 | least one message in the queue, then it is copied to the buffer, the size is |
---|
860 | set to return the length of the message in bytes, and this directive returns |
---|
861 | immediately with the :c:macro:`RTEMS_SUCCESSFUL` status code. The buffer has |
---|
862 | to be big enough to receive a message of the maximum length with respect to |
---|
863 | this message queue. |
---|
864 | |
---|
865 | If the calling task chooses to return immediately and the queue is empty, then |
---|
866 | the directive returns immediately with the :c:macro:`RTEMS_UNSATISFIED` status |
---|
867 | code. If the calling task chooses to wait at the message queue and the queue |
---|
868 | is empty, then the calling task is placed on the message wait queue and |
---|
869 | blocked. If the queue was created with the :c:macro:`RTEMS_PRIORITY` option |
---|
870 | specified, then the calling task is inserted into the wait queue according to |
---|
871 | its priority. But, if the queue was created with the :c:macro:`RTEMS_FIFO` |
---|
872 | option specified, then the calling task is placed at the rear of the wait |
---|
873 | queue. |
---|
874 | |
---|
875 | .. rubric:: RETURN VALUES: |
---|
876 | |
---|
877 | :c:macro:`RTEMS_SUCCESSFUL` |
---|
878 | The requested operation was successful. |
---|
879 | |
---|
880 | :c:macro:`RTEMS_INVALID_ID` |
---|
881 | There was no queue associated with the identifier specified by ``id``. |
---|
882 | |
---|
883 | :c:macro:`RTEMS_INVALID_ADDRESS` |
---|
884 | The ``buffer`` parameter was `NULL |
---|
885 | <https://en.cppreference.com/w/c/types/NULL>`_. |
---|
886 | |
---|
887 | :c:macro:`RTEMS_INVALID_ADDRESS` |
---|
888 | The ``size`` parameter was `NULL |
---|
889 | <https://en.cppreference.com/w/c/types/NULL>`_. |
---|
890 | |
---|
891 | :c:macro:`RTEMS_UNSATISFIED` |
---|
892 | The queue was empty. |
---|
893 | |
---|
894 | :c:macro:`RTEMS_TIMEOUT` |
---|
895 | The timeout happened while the calling task was waiting to receive a |
---|
896 | message |
---|
897 | |
---|
898 | :c:macro:`RTEMS_OBJECT_WAS_DELETED` |
---|
899 | The queue was deleted while the calling task was waiting to receive a |
---|
900 | message. |
---|
901 | |
---|
902 | .. rubric:: CONSTRAINTS: |
---|
903 | |
---|
904 | The following constraints apply to this directive: |
---|
905 | |
---|
906 | * When a local queue is accessed and the :c:macro:`RTEMS_NO_WAIT` option is |
---|
907 | set, the directive may be called from within interrupt context. |
---|
908 | |
---|
909 | * The directive may be called from within task context. |
---|
910 | |
---|
911 | * When the request cannot be immediately satisfied and the |
---|
912 | :c:macro:`RTEMS_WAIT` option is set, the calling task blocks at some point |
---|
913 | during the directive call. |
---|
914 | |
---|
915 | * The timeout functionality of the directive requires a :term:`clock tick`. |
---|
916 | |
---|
917 | * When the directive operates on a remote object, the directive sends a message |
---|
918 | to the remote node and waits for a reply. This will preempt the calling |
---|
919 | task. |
---|
920 | |
---|
921 | .. Generated from spec:/rtems/message/if/get-number-pending |
---|
922 | |
---|
923 | .. raw:: latex |
---|
924 | |
---|
925 | \clearpage |
---|
926 | |
---|
927 | .. index:: rtems_message_queue_get_number_pending() |
---|
928 | .. index:: get number of pending messages |
---|
929 | |
---|
930 | .. _InterfaceRtemsMessageQueueGetNumberPending: |
---|
931 | |
---|
932 | rtems_message_queue_get_number_pending() |
---|
933 | ---------------------------------------- |
---|
934 | |
---|
935 | Gets the number of messages pending on the queue. |
---|
936 | |
---|
937 | .. rubric:: CALLING SEQUENCE: |
---|
938 | |
---|
939 | .. code-block:: c |
---|
940 | |
---|
941 | rtems_status_code rtems_message_queue_get_number_pending( |
---|
942 | rtems_id id, |
---|
943 | uint32_t *count |
---|
944 | ); |
---|
945 | |
---|
946 | .. rubric:: PARAMETERS: |
---|
947 | |
---|
948 | ``id`` |
---|
949 | This parameter is the queue identifier. |
---|
950 | |
---|
951 | ``count`` |
---|
952 | This parameter is the pointer to an `uint32_t |
---|
953 | <https://en.cppreference.com/w/c/types/integer>`_ object. When the |
---|
954 | directive call is successful, the number of pending messages will be stored |
---|
955 | in this object. |
---|
956 | |
---|
957 | .. rubric:: DESCRIPTION: |
---|
958 | |
---|
959 | This directive returns the number of messages pending on the queue specified by |
---|
960 | ``id`` in ``count``. If no messages are present on the queue, count is set to |
---|
961 | zero. |
---|
962 | |
---|
963 | .. rubric:: RETURN VALUES: |
---|
964 | |
---|
965 | :c:macro:`RTEMS_SUCCESSFUL` |
---|
966 | The requested operation was successful. |
---|
967 | |
---|
968 | :c:macro:`RTEMS_INVALID_ID` |
---|
969 | There was no queue associated with the identifier specified by ``id``. |
---|
970 | |
---|
971 | :c:macro:`RTEMS_INVALID_ADDRESS` |
---|
972 | The ``count`` parameter was `NULL |
---|
973 | <https://en.cppreference.com/w/c/types/NULL>`_. |
---|
974 | |
---|
975 | .. rubric:: CONSTRAINTS: |
---|
976 | |
---|
977 | The following constraints apply to this directive: |
---|
978 | |
---|
979 | * The directive may be called from within task context. |
---|
980 | |
---|
981 | * The directive may be called from within interrupt context. |
---|
982 | |
---|
983 | * When the directive operates on a remote object, the directive sends a message |
---|
984 | to the remote node and waits for a reply. This will preempt the calling |
---|
985 | task. |
---|
986 | |
---|
987 | .. Generated from spec:/rtems/message/if/flush |
---|
988 | |
---|
989 | .. raw:: latex |
---|
990 | |
---|
991 | \clearpage |
---|
992 | |
---|
993 | .. index:: rtems_message_queue_flush() |
---|
994 | .. index:: flush messages on a queue |
---|
995 | |
---|
996 | .. _InterfaceRtemsMessageQueueFlush: |
---|
997 | |
---|
998 | rtems_message_queue_flush() |
---|
999 | --------------------------- |
---|
1000 | |
---|
1001 | Flushes all messages on the queue. |
---|
1002 | |
---|
1003 | .. rubric:: CALLING SEQUENCE: |
---|
1004 | |
---|
1005 | .. code-block:: c |
---|
1006 | |
---|
1007 | rtems_status_code rtems_message_queue_flush( rtems_id id, uint32_t *count ); |
---|
1008 | |
---|
1009 | .. rubric:: PARAMETERS: |
---|
1010 | |
---|
1011 | ``id`` |
---|
1012 | This parameter is the queue identifier. |
---|
1013 | |
---|
1014 | ``count`` |
---|
1015 | This parameter is the pointer to an `uint32_t |
---|
1016 | <https://en.cppreference.com/w/c/types/integer>`_ object. When the |
---|
1017 | directive call is successful, the number of pending messages removed from |
---|
1018 | the queue will be stored in this object. |
---|
1019 | |
---|
1020 | .. rubric:: DESCRIPTION: |
---|
1021 | |
---|
1022 | This directive removes all pending messages from the queue specified by ``id``. |
---|
1023 | The number of messages removed is returned in ``count``. If no messages are |
---|
1024 | present on the queue, count is set to zero. |
---|
1025 | |
---|
1026 | .. rubric:: RETURN VALUES: |
---|
1027 | |
---|
1028 | :c:macro:`RTEMS_SUCCESSFUL` |
---|
1029 | The requested operation was successful. |
---|
1030 | |
---|
1031 | :c:macro:`RTEMS_INVALID_ID` |
---|
1032 | There was no queue associated with the identifier specified by ``id``. |
---|
1033 | |
---|
1034 | :c:macro:`RTEMS_INVALID_ADDRESS` |
---|
1035 | The ``count`` parameter was `NULL |
---|
1036 | <https://en.cppreference.com/w/c/types/NULL>`_. |
---|
1037 | |
---|
1038 | .. rubric:: NOTES: |
---|
1039 | |
---|
1040 | The directive does not flush tasks waiting to receive a message from the |
---|
1041 | :term:`wait queue` of the message queue. |
---|
1042 | |
---|
1043 | .. rubric:: CONSTRAINTS: |
---|
1044 | |
---|
1045 | The following constraints apply to this directive: |
---|
1046 | |
---|
1047 | * The directive may be called from within interrupt context. |
---|
1048 | |
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1049 | * The directive may be called from within device driver initialization context. |
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1050 | |
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1051 | * The directive may be called from within task context. |
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1052 | |
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1053 | * The directive will not cause the calling task to be preempted. |
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1054 | |
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1055 | .. Generated from spec:/rtems/message/if/buffer |
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1056 | |
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1057 | .. raw:: latex |
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1058 | |
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1059 | \clearpage |
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1060 | |
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1061 | .. index:: RTEMS_MESSAGE_QUEUE_BUFFER() |
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1062 | |
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1063 | .. _InterfaceRTEMSMESSAGEQUEUEBUFFER: |
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1064 | |
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1065 | RTEMS_MESSAGE_QUEUE_BUFFER() |
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1066 | ---------------------------- |
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1067 | |
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1068 | Defines a structure which can be used as a message queue buffer for messages of |
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1069 | the specified maximum size. |
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1070 | |
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1071 | .. rubric:: CALLING SEQUENCE: |
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1072 | |
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1073 | .. code-block:: c |
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1074 | |
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1075 | #define RTEMS_MESSAGE_QUEUE_BUFFER( maximum_message_size ) |
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1076 | |
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1077 | .. rubric:: PARAMETERS: |
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1078 | |
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1079 | ``maximum_message_size`` |
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1080 | This parameter is the maximum message size in bytes. |
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1081 | |
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1082 | .. rubric:: NOTES: |
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1083 | |
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1084 | Use this macro to define the message buffer storage area for |
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1085 | :ref:`InterfaceRtemsMessageQueueConstruct`. |
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