2 FreeRTOS V7.4.1 - Copyright (C) 2013 Real Time Engineers Ltd.
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4 FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME. PLEASE VISIT
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5 http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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7 ***************************************************************************
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9 * FreeRTOS tutorial books are available in pdf and paperback. *
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10 * Complete, revised, and edited pdf reference manuals are also *
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13 * Purchasing FreeRTOS documentation will not only help you, by *
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14 * ensuring you get running as quickly as possible and with an *
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15 * in-depth knowledge of how to use FreeRTOS, it will also help *
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16 * the FreeRTOS project to continue with its mission of providing *
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17 * professional grade, cross platform, de facto standard solutions *
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18 * for microcontrollers - completely free of charge! *
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20 * >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
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22 * Thank you for using FreeRTOS, and thank you for your support! *
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24 ***************************************************************************
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27 This file is part of the FreeRTOS distribution.
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29 FreeRTOS is free software; you can redistribute it and/or modify it under
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30 the terms of the GNU General Public License (version 2) as published by the
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31 Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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33 >>>>>>NOTE<<<<<< The modification to the GPL is included to allow you to
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34 distribute a combined work that includes FreeRTOS without being obliged to
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35 provide the source code for proprietary components outside of the FreeRTOS
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38 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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39 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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40 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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41 details. You should have received a copy of the GNU General Public License
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42 and the FreeRTOS license exception along with FreeRTOS; if not it can be
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43 viewed here: http://www.freertos.org/a00114.html and also obtained by
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44 writing to Real Time Engineers Ltd., contact details for whom are available
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45 on the FreeRTOS WEB site.
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49 ***************************************************************************
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51 * Having a problem? Start by reading the FAQ "My application does *
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52 * not run, what could be wrong?" *
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54 * http://www.FreeRTOS.org/FAQHelp.html *
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56 ***************************************************************************
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59 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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60 license and Real Time Engineers Ltd. contact details.
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62 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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63 including FreeRTOS+Trace - an indispensable productivity tool, and our new
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64 fully thread aware and reentrant UDP/IP stack.
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66 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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67 Integrity Systems, who sell the code with commercial support,
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68 indemnification and middleware, under the OpenRTOS brand.
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70 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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71 engineered and independently SIL3 certified version for use in safety and
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72 mission critical applications that require provable dependability.
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76 * This is a version of BlockQ.c that uses the alternative (Alt) API.
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78 * Creates six tasks that operate on three queues as follows:
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80 * The first two tasks send and receive an incrementing number to/from a queue.
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81 * One task acts as a producer and the other as the consumer. The consumer is a
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82 * higher priority than the producer and is set to block on queue reads. The queue
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83 * only has space for one item - as soon as the producer posts a message on the
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84 * queue the consumer will unblock, pre-empt the producer, and remove the item.
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86 * The second two tasks work the other way around. Again the queue used only has
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87 * enough space for one item. This time the consumer has a lower priority than the
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88 * producer. The producer will try to post on the queue blocking when the queue is
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89 * full. When the consumer wakes it will remove the item from the queue, causing
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90 * the producer to unblock, pre-empt the consumer, and immediately re-fill the
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93 * The last two tasks use the same queue producer and consumer functions. This time the queue has
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94 * enough space for lots of items and the tasks operate at the same priority. The
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95 * producer will execute, placing items into the queue. The consumer will start
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96 * executing when either the queue becomes full (causing the producer to block) or
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97 * a context switch occurs (tasks of the same priority will time slice).
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102 #include <stdlib.h>
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104 /* Scheduler include files. */
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105 #include "FreeRTOS.h"
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109 /* Demo program include files. */
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110 #include "AltBlckQ.h"
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112 #define blckqSTACK_SIZE configMINIMAL_STACK_SIZE
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113 #define blckqNUM_TASK_SETS ( 3 )
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115 /* Structure used to pass parameters to the blocking queue tasks. */
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116 typedef struct BLOCKING_QUEUE_PARAMETERS
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118 xQueueHandle xQueue; /*< The queue to be used by the task. */
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119 portTickType xBlockTime; /*< The block time to use on queue reads/writes. */
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120 volatile portSHORT *psCheckVariable; /*< Incremented on each successful cycle to check the task is still running. */
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121 } xBlockingQueueParameters;
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123 /* Task function that creates an incrementing number and posts it on a queue. */
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124 static portTASK_FUNCTION_PROTO( vBlockingQueueProducer, pvParameters );
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126 /* Task function that removes the incrementing number from a queue and checks that
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127 it is the expected number. */
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128 static portTASK_FUNCTION_PROTO( vBlockingQueueConsumer, pvParameters );
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130 /* Variables which are incremented each time an item is removed from a queue, and
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131 found to be the expected value.
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132 These are used to check that the tasks are still running. */
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133 static volatile portSHORT sBlockingConsumerCount[ blckqNUM_TASK_SETS ] = { ( unsigned portSHORT ) 0, ( unsigned portSHORT ) 0, ( unsigned portSHORT ) 0 };
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135 /* Variable which are incremented each time an item is posted on a queue. These
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136 are used to check that the tasks are still running. */
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137 static volatile portSHORT sBlockingProducerCount[ blckqNUM_TASK_SETS ] = { ( unsigned portSHORT ) 0, ( unsigned portSHORT ) 0, ( unsigned portSHORT ) 0 };
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139 /*-----------------------------------------------------------*/
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141 void vStartAltBlockingQueueTasks( unsigned portBASE_TYPE uxPriority )
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143 xBlockingQueueParameters *pxQueueParameters1, *pxQueueParameters2;
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144 xBlockingQueueParameters *pxQueueParameters3, *pxQueueParameters4;
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145 xBlockingQueueParameters *pxQueueParameters5, *pxQueueParameters6;
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146 const unsigned portBASE_TYPE uxQueueSize1 = 1, uxQueueSize5 = 5;
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147 const portTickType xBlockTime = ( portTickType ) 1000 / portTICK_RATE_MS;
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148 const portTickType xDontBlock = ( portTickType ) 0;
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150 /* Create the first two tasks as described at the top of the file. */
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152 /* First create the structure used to pass parameters to the consumer tasks. */
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153 pxQueueParameters1 = ( xBlockingQueueParameters * ) pvPortMalloc( sizeof( xBlockingQueueParameters ) );
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155 /* Create the queue used by the first two tasks to pass the incrementing number.
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156 Pass a pointer to the queue in the parameter structure. */
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157 pxQueueParameters1->xQueue = xQueueCreate( uxQueueSize1, ( unsigned portBASE_TYPE ) sizeof( unsigned portSHORT ) );
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159 /* The consumer is created first so gets a block time as described above. */
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160 pxQueueParameters1->xBlockTime = xBlockTime;
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162 /* Pass in the variable that this task is going to increment so we can check it
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163 is still running. */
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164 pxQueueParameters1->psCheckVariable = &( sBlockingConsumerCount[ 0 ] );
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166 /* Create the structure used to pass parameters to the producer task. */
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167 pxQueueParameters2 = ( xBlockingQueueParameters * ) pvPortMalloc( sizeof( xBlockingQueueParameters ) );
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169 /* Pass the queue to this task also, using the parameter structure. */
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170 pxQueueParameters2->xQueue = pxQueueParameters1->xQueue;
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172 /* The producer is not going to block - as soon as it posts the consumer will
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173 wake and remove the item so the producer should always have room to post. */
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174 pxQueueParameters2->xBlockTime = xDontBlock;
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176 /* Pass in the variable that this task is going to increment so we can check
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177 it is still running. */
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178 pxQueueParameters2->psCheckVariable = &( sBlockingProducerCount[ 0 ] );
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181 /* Note the producer has a lower priority than the consumer when the tasks are
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183 xTaskCreate( vBlockingQueueConsumer, ( signed portCHAR * ) "QConsB1", blckqSTACK_SIZE, ( void * ) pxQueueParameters1, uxPriority, NULL );
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184 xTaskCreate( vBlockingQueueProducer, ( signed portCHAR * ) "QProdB2", blckqSTACK_SIZE, ( void * ) pxQueueParameters2, tskIDLE_PRIORITY, NULL );
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188 /* Create the second two tasks as described at the top of the file. This uses
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189 the same mechanism but reverses the task priorities. */
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191 pxQueueParameters3 = ( xBlockingQueueParameters * ) pvPortMalloc( sizeof( xBlockingQueueParameters ) );
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192 pxQueueParameters3->xQueue = xQueueCreate( uxQueueSize1, ( unsigned portBASE_TYPE ) sizeof( unsigned portSHORT ) );
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193 pxQueueParameters3->xBlockTime = xDontBlock;
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194 pxQueueParameters3->psCheckVariable = &( sBlockingProducerCount[ 1 ] );
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196 pxQueueParameters4 = ( xBlockingQueueParameters * ) pvPortMalloc( sizeof( xBlockingQueueParameters ) );
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197 pxQueueParameters4->xQueue = pxQueueParameters3->xQueue;
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198 pxQueueParameters4->xBlockTime = xBlockTime;
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199 pxQueueParameters4->psCheckVariable = &( sBlockingConsumerCount[ 1 ] );
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201 xTaskCreate( vBlockingQueueConsumer, ( signed portCHAR * ) "QProdB3", blckqSTACK_SIZE, ( void * ) pxQueueParameters3, tskIDLE_PRIORITY, NULL );
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202 xTaskCreate( vBlockingQueueProducer, ( signed portCHAR * ) "QConsB4", blckqSTACK_SIZE, ( void * ) pxQueueParameters4, uxPriority, NULL );
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206 /* Create the last two tasks as described above. The mechanism is again just
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207 the same. This time both parameter structures are given a block time. */
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208 pxQueueParameters5 = ( xBlockingQueueParameters * ) pvPortMalloc( sizeof( xBlockingQueueParameters ) );
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209 pxQueueParameters5->xQueue = xQueueCreate( uxQueueSize5, ( unsigned portBASE_TYPE ) sizeof( unsigned portSHORT ) );
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210 pxQueueParameters5->xBlockTime = xBlockTime;
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211 pxQueueParameters5->psCheckVariable = &( sBlockingProducerCount[ 2 ] );
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213 pxQueueParameters6 = ( xBlockingQueueParameters * ) pvPortMalloc( sizeof( xBlockingQueueParameters ) );
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214 pxQueueParameters6->xQueue = pxQueueParameters5->xQueue;
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215 pxQueueParameters6->xBlockTime = xBlockTime;
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216 pxQueueParameters6->psCheckVariable = &( sBlockingConsumerCount[ 2 ] );
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218 xTaskCreate( vBlockingQueueProducer, ( signed portCHAR * ) "QProdB5", blckqSTACK_SIZE, ( void * ) pxQueueParameters5, tskIDLE_PRIORITY, NULL );
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219 xTaskCreate( vBlockingQueueConsumer, ( signed portCHAR * ) "QConsB6", blckqSTACK_SIZE, ( void * ) pxQueueParameters6, tskIDLE_PRIORITY, NULL );
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221 /*-----------------------------------------------------------*/
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223 static portTASK_FUNCTION( vBlockingQueueProducer, pvParameters )
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225 unsigned portSHORT usValue = 0;
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226 xBlockingQueueParameters *pxQueueParameters;
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227 portSHORT sErrorEverOccurred = pdFALSE;
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230 void vPrintDisplayMessage( const portCHAR * const * ppcMessageToSend );
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232 const portCHAR * const pcTaskStartMsg = "Alt blocking queue producer task started.\r\n";
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234 /* Queue a message for printing to say the task has started. */
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235 vPrintDisplayMessage( &pcTaskStartMsg );
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238 pxQueueParameters = ( xBlockingQueueParameters * ) pvParameters;
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242 if( xQueueAltSendToBack( pxQueueParameters->xQueue, ( void * ) &usValue, pxQueueParameters->xBlockTime ) != pdPASS )
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244 sErrorEverOccurred = pdTRUE;
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248 /* We have successfully posted a message, so increment the variable
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249 used to check we are still running. */
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250 if( sErrorEverOccurred == pdFALSE )
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252 ( *pxQueueParameters->psCheckVariable )++;
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255 /* Increment the variable we are going to post next time round. The
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256 consumer will expect the numbers to follow in numerical order. */
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261 /*-----------------------------------------------------------*/
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263 static portTASK_FUNCTION( vBlockingQueueConsumer, pvParameters )
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265 unsigned portSHORT usData, usExpectedValue = 0;
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266 xBlockingQueueParameters *pxQueueParameters;
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267 portSHORT sErrorEverOccurred = pdFALSE;
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270 void vPrintDisplayMessage( const portCHAR * const * ppcMessageToSend );
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272 const portCHAR * const pcTaskStartMsg = "Alt blocking queue consumer task started.\r\n";
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274 /* Queue a message for printing to say the task has started. */
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275 vPrintDisplayMessage( &pcTaskStartMsg );
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278 pxQueueParameters = ( xBlockingQueueParameters * ) pvParameters;
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282 if( xQueueAltReceive( pxQueueParameters->xQueue, &usData, pxQueueParameters->xBlockTime ) == pdPASS )
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284 if( usData != usExpectedValue )
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287 usExpectedValue = usData;
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289 sErrorEverOccurred = pdTRUE;
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293 /* We have successfully received a message, so increment the
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294 variable used to check we are still running. */
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295 if( sErrorEverOccurred == pdFALSE )
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297 ( *pxQueueParameters->psCheckVariable )++;
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300 /* Increment the value we expect to remove from the queue next time
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307 /*-----------------------------------------------------------*/
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309 /* This is called to check that all the created tasks are still running. */
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310 portBASE_TYPE xAreAltBlockingQueuesStillRunning( void )
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312 static portSHORT sLastBlockingConsumerCount[ blckqNUM_TASK_SETS ] = { ( unsigned portSHORT ) 0, ( unsigned portSHORT ) 0, ( unsigned portSHORT ) 0 };
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313 static portSHORT sLastBlockingProducerCount[ blckqNUM_TASK_SETS ] = { ( unsigned portSHORT ) 0, ( unsigned portSHORT ) 0, ( unsigned portSHORT ) 0 };
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314 portBASE_TYPE xReturn = pdPASS, xTasks;
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316 /* Not too worried about mutual exclusion on these variables as they are 16
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317 bits and we are only reading them. We also only care to see if they have
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320 Loop through each check variable to and return pdFALSE if any are found not
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321 to have changed since the last call. */
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323 for( xTasks = 0; xTasks < blckqNUM_TASK_SETS; xTasks++ )
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325 if( sBlockingConsumerCount[ xTasks ] == sLastBlockingConsumerCount[ xTasks ] )
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329 sLastBlockingConsumerCount[ xTasks ] = sBlockingConsumerCount[ xTasks ];
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332 if( sBlockingProducerCount[ xTasks ] == sLastBlockingProducerCount[ xTasks ] )
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336 sLastBlockingProducerCount[ xTasks ] = sBlockingProducerCount[ xTasks ];
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