2 * FreeRTOS Kernel V10.3.0
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3 * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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5 * Permission is hereby granted, free of charge, to any person obtaining a copy of
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6 * this software and associated documentation files (the "Software"), to deal in
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7 * the Software without restriction, including without limitation the rights to
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8 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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9 * the Software, and to permit persons to whom the Software is furnished to do so,
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10 * subject to the following conditions:
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12 * The above copyright notice and this permission notice shall be included in all
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13 * copies or substantial portions of the Software.
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15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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17 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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18 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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19 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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20 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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22 * http://www.FreeRTOS.org
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23 * http://aws.amazon.com/freertos
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25 * 1 tab == 4 spaces!
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29 * Creates six tasks that operate on three queues as follows:
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31 * The first two tasks send and receive an incrementing number to/from a queue.
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32 * One task acts as a producer and the other as the consumer. The consumer is a
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33 * higher priority than the producer and is set to block on queue reads. The queue
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34 * only has space for one item - as soon as the producer posts a message on the
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35 * queue the consumer will unblock, pre-empt the producer, and remove the item.
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37 * The second two tasks work the other way around. Again the queue used only has
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38 * enough space for one item. This time the consumer has a lower priority than the
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39 * producer. The producer will try to post on the queue blocking when the queue is
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40 * full. When the consumer wakes it will remove the item from the queue, causing
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41 * the producer to unblock, pre-empt the consumer, and immediately re-fill the
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44 * The last two tasks use the same queue producer and consumer functions. This time the queue has
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45 * enough space for lots of items and the tasks operate at the same priority. The
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46 * producer will execute, placing items into the queue. The consumer will start
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47 * executing when either the queue becomes full (causing the producer to block) or
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48 * a context switch occurs (tasks of the same priority will time slice).
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50 * \page BlockQC blockQ.c
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51 * \ingroup DemoFiles
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58 + Reversed the priority and block times of the second two demo tasks so
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59 they operate as per the description above.
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63 + Delay periods are now specified using variables and constants of
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64 TickType_t rather than unsigned long.
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68 + The second set of tasks were created the wrong way around. This has been
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75 /* Scheduler include files. */
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76 #include "FreeRTOS.h"
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80 /* Demo program include files. */
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84 #define blckqSTACK_SIZE ( ( unsigned short ) configMINIMAL_STACK_SIZE )
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85 #define blckqNUM_TASK_SETS ( 3 )
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87 /* Structure used to pass parameters to the blocking queue tasks. */
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88 typedef struct BLOCKING_QUEUE_PARAMETERS
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90 QueueHandle_t xQueue; /*< The queue to be used by the task. */
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91 TickType_t xBlockTime; /*< The block time to use on queue reads/writes. */
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92 volatile short *psCheckVariable; /*< Incremented on each successful cycle to check the task is still running. */
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93 } xBlockingQueueParameters;
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95 /* Task function that creates an incrementing number and posts it on a queue. */
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96 static void vBlockingQueueProducer( void *pvParameters );
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98 /* Task function that removes the incrementing number from a queue and checks that
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99 it is the expected number. */
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100 static void vBlockingQueueConsumer( void *pvParameters );
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102 /* Variables which are incremented each time an item is removed from a queue, and
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103 found to be the expected value.
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104 These are used to check that the tasks are still running. */
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105 static volatile short sBlockingConsumerCount[ blckqNUM_TASK_SETS ] = { ( short ) 0, ( short ) 0, ( short ) 0 };
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107 /* Variable which are incremented each time an item is posted on a queue. These
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108 are used to check that the tasks are still running. */
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109 static volatile short sBlockingProducerCount[ blckqNUM_TASK_SETS ] = { ( short ) 0, ( short ) 0, ( short ) 0 };
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111 /*-----------------------------------------------------------*/
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113 void vStartBlockingQueueTasks( unsigned portBASE_TYPE uxPriority )
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115 xBlockingQueueParameters *pxQueueParameters1, *pxQueueParameters2;
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116 xBlockingQueueParameters *pxQueueParameters3, *pxQueueParameters4;
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117 xBlockingQueueParameters *pxQueueParameters5, *pxQueueParameters6;
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118 const unsigned portBASE_TYPE uxQueueSize1 = 1, uxQueueSize5 = 5;
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119 const TickType_t xBlockTime = ( TickType_t ) 1000 / portTICK_PERIOD_MS;
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120 const TickType_t xDontBlock = ( TickType_t ) 0;
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122 /* Create the first two tasks as described at the top of the file. */
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124 /* First create the structure used to pass parameters to the consumer tasks. */
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125 pxQueueParameters1 = ( xBlockingQueueParameters * ) pvPortMalloc( sizeof( xBlockingQueueParameters ) );
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127 /* Create the queue used by the first two tasks to pass the incrementing number.
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128 Pass a pointer to the queue in the parameter structure. */
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129 pxQueueParameters1->xQueue = xQueueCreate( uxQueueSize1, ( unsigned portBASE_TYPE ) sizeof( unsigned short ) );
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131 /* The consumer is created first so gets a block time as described above. */
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132 pxQueueParameters1->xBlockTime = xBlockTime;
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134 /* Pass in the variable that this task is going to increment so we can check it
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135 is still running. */
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136 pxQueueParameters1->psCheckVariable = &( sBlockingConsumerCount[ 0 ] );
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138 /* Create the structure used to pass parameters to the producer task. */
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139 pxQueueParameters2 = ( xBlockingQueueParameters * ) pvPortMalloc( sizeof( xBlockingQueueParameters ) );
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141 /* Pass the queue to this task also, using the parameter structure. */
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142 pxQueueParameters2->xQueue = pxQueueParameters1->xQueue;
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144 /* The producer is not going to block - as soon as it posts the consumer will
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145 wake and remove the item so the producer should always have room to post. */
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146 pxQueueParameters2->xBlockTime = xDontBlock;
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148 /* Pass in the variable that this task is going to increment so we can check
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149 it is still running. */
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150 pxQueueParameters2->psCheckVariable = &( sBlockingProducerCount[ 0 ] );
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153 /* Note the producer has a lower priority than the consumer when the tasks are
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155 xTaskCreate( vBlockingQueueConsumer, "QConsB1", blckqSTACK_SIZE, ( void * ) pxQueueParameters1, uxPriority, NULL );
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156 xTaskCreate( vBlockingQueueProducer, "QProdB2", blckqSTACK_SIZE, ( void * ) pxQueueParameters2, tskIDLE_PRIORITY, NULL );
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160 /* Create the second two tasks as described at the top of the file. This uses
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161 the same mechanism but reverses the task priorities. */
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163 pxQueueParameters3 = ( xBlockingQueueParameters * ) pvPortMalloc( sizeof( xBlockingQueueParameters ) );
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164 pxQueueParameters3->xQueue = xQueueCreate( uxQueueSize1, ( unsigned portBASE_TYPE ) sizeof( unsigned short ) );
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165 pxQueueParameters3->xBlockTime = xDontBlock;
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166 pxQueueParameters3->psCheckVariable = &( sBlockingProducerCount[ 1 ] );
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168 pxQueueParameters4 = ( xBlockingQueueParameters * ) pvPortMalloc( sizeof( xBlockingQueueParameters ) );
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169 pxQueueParameters4->xQueue = pxQueueParameters3->xQueue;
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170 pxQueueParameters4->xBlockTime = xBlockTime;
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171 pxQueueParameters4->psCheckVariable = &( sBlockingConsumerCount[ 1 ] );
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173 xTaskCreate( vBlockingQueueProducer, "QProdB3", blckqSTACK_SIZE, ( void * ) pxQueueParameters3, tskIDLE_PRIORITY, NULL );
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174 xTaskCreate( vBlockingQueueConsumer, "QConsB4", blckqSTACK_SIZE, ( void * ) pxQueueParameters4, uxPriority, NULL );
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178 /* Create the last two tasks as described above. The mechanism is again just
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179 the same. This time both parameter structures are given a block time. */
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180 pxQueueParameters5 = ( xBlockingQueueParameters * ) pvPortMalloc( sizeof( xBlockingQueueParameters ) );
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181 pxQueueParameters5->xQueue = xQueueCreate( uxQueueSize5, ( unsigned portBASE_TYPE ) sizeof( unsigned short ) );
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182 pxQueueParameters5->xBlockTime = xBlockTime;
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183 pxQueueParameters5->psCheckVariable = &( sBlockingProducerCount[ 2 ] );
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185 pxQueueParameters6 = ( xBlockingQueueParameters * ) pvPortMalloc( sizeof( xBlockingQueueParameters ) );
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186 pxQueueParameters6->xQueue = pxQueueParameters5->xQueue;
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187 pxQueueParameters6->xBlockTime = xBlockTime;
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188 pxQueueParameters6->psCheckVariable = &( sBlockingConsumerCount[ 2 ] );
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190 xTaskCreate( vBlockingQueueProducer, "QProdB5", blckqSTACK_SIZE, ( void * ) pxQueueParameters5, tskIDLE_PRIORITY, NULL );
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191 xTaskCreate( vBlockingQueueConsumer, "QConsB6", blckqSTACK_SIZE, ( void * ) pxQueueParameters6, tskIDLE_PRIORITY, NULL );
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193 /*-----------------------------------------------------------*/
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195 static void vBlockingQueueProducer( void *pvParameters )
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197 unsigned short usValue = 0;
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198 xBlockingQueueParameters *pxQueueParameters;
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199 const char * const pcTaskStartMsg = "Blocking queue producer started.\r\n";
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200 const char * const pcTaskErrorMsg = "Could not post on blocking queue\r\n";
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201 short sErrorEverOccurred = pdFALSE;
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203 pxQueueParameters = ( xBlockingQueueParameters * ) pvParameters;
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205 /* Queue a message for printing to say the task has started. */
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206 vPrintDisplayMessage( &pcTaskStartMsg );
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210 if( xQueueSendToBack( pxQueueParameters->xQueue, ( void * ) &usValue, pxQueueParameters->xBlockTime ) != pdPASS )
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212 vPrintDisplayMessage( &pcTaskErrorMsg );
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213 sErrorEverOccurred = pdTRUE;
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217 /* We have successfully posted a message, so increment the variable
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218 used to check we are still running. */
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219 if( sErrorEverOccurred == pdFALSE )
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221 ( *pxQueueParameters->psCheckVariable )++;
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224 /* Increment the variable we are going to post next time round. The
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225 consumer will expect the numbers to follow in numerical order. */
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230 /*-----------------------------------------------------------*/
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232 static void vBlockingQueueConsumer( void *pvParameters )
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234 unsigned short usData, usExpectedValue = 0;
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235 xBlockingQueueParameters *pxQueueParameters;
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236 const char * const pcTaskStartMsg = "Blocking queue consumer started.\r\n";
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237 const char * const pcTaskErrorMsg = "Incorrect value received on blocking queue.\r\n";
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238 short sErrorEverOccurred = pdFALSE;
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240 /* Queue a message for printing to say the task has started. */
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241 vPrintDisplayMessage( &pcTaskStartMsg );
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243 pxQueueParameters = ( xBlockingQueueParameters * ) pvParameters;
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247 if( xQueueReceive( pxQueueParameters->xQueue, &usData, pxQueueParameters->xBlockTime ) == pdPASS )
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249 if( usData != usExpectedValue )
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251 vPrintDisplayMessage( &pcTaskErrorMsg );
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254 usExpectedValue = usData;
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256 sErrorEverOccurred = pdTRUE;
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260 /* We have successfully received a message, so increment the
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261 variable used to check we are still running. */
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262 if( sErrorEverOccurred == pdFALSE )
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264 ( *pxQueueParameters->psCheckVariable )++;
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267 /* Increment the value we expect to remove from the queue next time
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274 /*-----------------------------------------------------------*/
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276 /* This is called to check that all the created tasks are still running. */
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277 portBASE_TYPE xAreBlockingQueuesStillRunning( void )
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279 static short sLastBlockingConsumerCount[ blckqNUM_TASK_SETS ] = { ( short ) 0, ( short ) 0, ( short ) 0 };
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280 static short sLastBlockingProducerCount[ blckqNUM_TASK_SETS ] = { ( short ) 0, ( short ) 0, ( short ) 0 };
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281 portBASE_TYPE xReturn = pdPASS, xTasks;
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283 /* Not too worried about mutual exclusion on these variables as they are 16
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284 bits and we are only reading them. We also only care to see if they have
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287 Loop through each check variable and return pdFALSE if any are found not
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288 to have changed since the last call. */
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290 for( xTasks = 0; xTasks < blckqNUM_TASK_SETS; xTasks++ )
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292 if( sBlockingConsumerCount[ xTasks ] == sLastBlockingConsumerCount[ xTasks ] )
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296 sLastBlockingConsumerCount[ xTasks ] = sBlockingConsumerCount[ xTasks ];
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299 if( sBlockingProducerCount[ xTasks ] == sLastBlockingProducerCount[ xTasks ] )
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303 sLastBlockingProducerCount[ xTasks ] = sBlockingProducerCount[ xTasks ];
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