2 FreeRTOS V9.0.0rc1 - Copyright (C) 2016 Real Time Engineers Ltd.
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5 VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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7 This file is part of the FreeRTOS distribution.
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9 FreeRTOS is free software; you can redistribute it and/or modify it under
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10 the terms of the GNU General Public License (version 2) as published by the
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11 Free Software Foundation >>>> AND MODIFIED BY <<<< the FreeRTOS exception.
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13 ***************************************************************************
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14 >>! NOTE: The modification to the GPL is included to allow you to !<<
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15 >>! distribute a combined work that includes FreeRTOS without being !<<
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16 >>! obliged to provide the source code for proprietary components !<<
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17 >>! outside of the FreeRTOS kernel. !<<
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18 ***************************************************************************
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20 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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21 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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22 FOR A PARTICULAR PURPOSE. Full license text is available on the following
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23 link: http://www.freertos.org/a00114.html
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25 ***************************************************************************
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27 * FreeRTOS provides completely free yet professionally developed, *
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28 * robust, strictly quality controlled, supported, and cross *
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29 * platform software that is more than just the market leader, it *
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30 * is the industry's de facto standard. *
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32 * Help yourself get started quickly while simultaneously helping *
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33 * to support the FreeRTOS project by purchasing a FreeRTOS *
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34 * tutorial book, reference manual, or both: *
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35 * http://www.FreeRTOS.org/Documentation *
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37 ***************************************************************************
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39 http://www.FreeRTOS.org/FAQHelp.html - Having a problem? Start by reading
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40 the FAQ page "My application does not run, what could be wrong?". Have you
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41 defined configASSERT()?
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43 http://www.FreeRTOS.org/support - In return for receiving this top quality
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44 embedded software for free we request you assist our global community by
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45 participating in the support forum.
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47 http://www.FreeRTOS.org/training - Investing in training allows your team to
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48 be as productive as possible as early as possible. Now you can receive
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49 FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers
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50 Ltd, and the world's leading authority on the world's leading RTOS.
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52 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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53 including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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54 compatible FAT file system, and our tiny thread aware UDP/IP stack.
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56 http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
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57 Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.
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59 http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High
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60 Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS
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61 licenses offer ticketed support, indemnification and commercial middleware.
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63 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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64 engineered and independently SIL3 certified version for use in safety and
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65 mission critical applications that require provable dependability.
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74 #ifndef INC_FREERTOS_H
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75 #error "include FreeRTOS.h" must appear in source files before "include queue.h"
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84 * Type by which queues are referenced. For example, a call to xQueueCreate()
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85 * returns an QueueHandle_t variable that can then be used as a parameter to
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86 * xQueueSend(), xQueueReceive(), etc.
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88 typedef void * QueueHandle_t;
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91 * Type by which queue sets are referenced. For example, a call to
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92 * xQueueCreateSet() returns an xQueueSet variable that can then be used as a
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93 * parameter to xQueueSelectFromSet(), xQueueAddToSet(), etc.
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95 typedef void * QueueSetHandle_t;
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98 * Queue sets can contain both queues and semaphores, so the
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99 * QueueSetMemberHandle_t is defined as a type to be used where a parameter or
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100 * return value can be either an QueueHandle_t or an SemaphoreHandle_t.
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102 typedef void * QueueSetMemberHandle_t;
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104 /* For internal use only. */
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105 #define queueSEND_TO_BACK ( ( BaseType_t ) 0 )
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106 #define queueSEND_TO_FRONT ( ( BaseType_t ) 1 )
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107 #define queueOVERWRITE ( ( BaseType_t ) 2 )
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109 /* For internal use only. These definitions *must* match those in queue.c. */
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110 #define queueQUEUE_TYPE_BASE ( ( uint8_t ) 0U )
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111 #define queueQUEUE_TYPE_SET ( ( uint8_t ) 0U )
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112 #define queueQUEUE_TYPE_MUTEX ( ( uint8_t ) 1U )
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113 #define queueQUEUE_TYPE_COUNTING_SEMAPHORE ( ( uint8_t ) 2U )
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114 #define queueQUEUE_TYPE_BINARY_SEMAPHORE ( ( uint8_t ) 3U )
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115 #define queueQUEUE_TYPE_RECURSIVE_MUTEX ( ( uint8_t ) 4U )
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120 QueueHandle_t xQueueCreate(
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121 UBaseType_t uxQueueLength,
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122 UBaseType_t uxItemSize
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126 * Creates a new queue instance, and returns a handle by which the new queue
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127 * can be referenced.
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129 * Internally, within the FreeRTOS implementation, queue's use two blocks of
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130 * memory. The first block is used to hold the queue's data structures. The
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131 * second block is used to hold items placed into the queue. If a queue is
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132 * created using xQueueCreate() then both blocks of memory are automatically
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133 * dynamically allocated inside the xQueueCreate() function. (see
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134 * http://www.freertos.org/a00111.html). If a queue is created using
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135 * xQueueCreateStatic() then the application writer can instead optionally
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136 * provide the memory that will get used by the queue. xQueueCreateStatic()
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137 * therefore allows a queue to be created without using any dynamic memory
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140 * @param uxQueueLength The maximum number of items that the queue can contain.
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142 * @param uxItemSize The number of bytes each item in the queue will require.
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143 * Items are queued by copy, not by reference, so this is the number of bytes
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144 * that will be copied for each posted item. Each item on the queue must be
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147 * @return If the queue is successfully create then a handle to the newly
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148 * created queue is returned. If the queue cannot be created then 0 is
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159 void vATask( void *pvParameters )
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161 QueueHandle_t xQueue1, xQueue2;
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163 // Create a queue capable of containing 10 uint32_t values.
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164 xQueue1 = xQueueCreate( 10, sizeof( uint32_t ) );
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167 // Queue was not created and must not be used.
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170 // Create a queue capable of containing 10 pointers to AMessage structures.
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171 // These should be passed by pointer as they contain a lot of data.
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172 xQueue2 = xQueueCreate( 10, sizeof( struct AMessage * ) );
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175 // Queue was not created and must not be used.
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178 // ... Rest of task code.
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181 * \defgroup xQueueCreate xQueueCreate
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182 * \ingroup QueueManagement
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184 #if( configSUPPORT_DYNAMIC_ALLOCATION == 1 )
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185 #define xQueueCreate( uxQueueLength, uxItemSize ) xQueueGenericCreate( ( uxQueueLength ), ( uxItemSize ), ( queueQUEUE_TYPE_BASE ) )
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191 QueueHandle_t xQueueCreateStatic(
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192 UBaseType_t uxQueueLength,
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193 UBaseType_t uxItemSize,
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194 uint8_t *pucQueueStorageBuffer,
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195 StaticQueue_t *pxQueueBuffer
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199 * Creates a new queue instance, and returns a handle by which the new queue
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200 * can be referenced.
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202 * Internally, within the FreeRTOS implementation, queue's use two blocks of
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203 * memory. The first block is used to hold the queue's data structures. The
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204 * second block is used to hold items placed into the queue. If a queue is
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205 * created using xQueueCreate() then both blocks of memory are automatically
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206 * dynamically allocated inside the xQueueCreate() function. (see
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207 * http://www.freertos.org/a00111.html). If a queue is created using
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208 * xQueueCreateStatic() then the application writer can instead optionally
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209 * provide the memory that will get used by the queue. xQueueCreateStatic()
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210 * therefore allows a queue to be created without using any dynamic memory
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213 * @param uxQueueLength The maximum number of items that the queue can contain.
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215 * @param uxItemSize The number of bytes each item in the queue will require.
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216 * Items are queued by copy, not by reference, so this is the number of bytes
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217 * that will be copied for each posted item. Each item on the queue must be
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220 * @param pucQueueStorageBuffer If pucQueueStorageBuffer is NULL then the memory
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221 * used to hold items stored in the queue will be allocated dynamically, just as
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222 * when a queue is created using xQueueCreate(). If pxQueueStorageBuffer is not
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223 * NULL then it must point to a uint8_t array that is at least large enough to
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224 * hold the maximum number of items that can be in the queue at any one time -
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225 * which is ( uxQueueLength * uxItemsSize ) bytes.
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227 * @param pxQueueBuffer If pxQueueBuffer is NULL then the memory required to
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228 * hold the queue's data structures will be allocated dynamically, just as when
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229 * a queue is created using xQueueCreate(). If pxQueueBuffer is not NULL then
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230 * it must point to a variable of type StaticQueue_t, which will then be used to
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231 * hold the queue's data structure, removing the need for the memory to be
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232 * allocated dynamically.
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234 * @return If neither pucQueueStorageBuffer or pxQueueBuffer are NULL, then the
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235 * function will not attempt any dynamic memory allocation, and a handle to the
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236 * created queue will always be returned. If pucQueueStorageBuffer or
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237 * pxQueueBuffer is NULL then the function will attempt to dynamically allocate
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238 * one of both buffers. In this case, if the allocation succeeds then a handle
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239 * to the created queue will be returned, and if one of the the allocation fails
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240 * NULL will be returned.
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250 #define QUEUE_LENGTH 10
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251 #define ITEM_SIZE sizeof( uint32_t )
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253 // xQueueBuffer will hold the queue structure.
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254 StaticQueue_t xQueueBuffer;
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256 // ucQueueStorage will hold the items posted to the queue. Must be at least
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257 // [(queue length) * ( queue item size)] bytes long.
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258 uint8_t ucQueueStorage[ QUEUE_LENGTH * ITEM_SIZE ];
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260 void vATask( void *pvParameters )
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262 QueueHandle_t xQueue1;
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264 // Create a queue capable of containing 10 uint32_t values.
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265 xQueue1 = xQueueCreate( QUEUE_LENGTH, // The number of items the queue can hold.
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266 ITEM_SIZE // The size of each item in the queue
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267 &( ucQueueStorage[ 0 ] ), // The buffer that will hold the items in the queue.
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268 &xQueueBuffer ); // The buffer that will hold the queue structure.
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270 // The queue is guaranteed to be created successfully as no dynamic memory
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271 // allocation was used. Therefore xQueue1 is now a handle to a valid queue.
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273 // ... Rest of task code.
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276 * \defgroup xQueueCreateStatic xQueueCreateStatic
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277 * \ingroup QueueManagement
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279 #if( configSUPPORT_STATIC_ALLOCATION == 1 )
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280 #define xQueueCreateStatic( uxQueueLength, uxItemSize, pucQueueStorage, pxQueueBuffer ) xQueueGenericCreateStatic( ( uxQueueLength ), ( uxItemSize ), ( pucQueueStorage ), ( pxQueueBuffer ), ( queueQUEUE_TYPE_BASE ) )
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281 #endif /* configSUPPORT_STATIC_ALLOCATION */
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286 BaseType_t xQueueSendToToFront(
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287 QueueHandle_t xQueue,
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288 const void *pvItemToQueue,
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289 TickType_t xTicksToWait
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293 * This is a macro that calls xQueueGenericSend().
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295 * Post an item to the front of a queue. The item is queued by copy, not by
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296 * reference. This function must not be called from an interrupt service
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297 * routine. See xQueueSendFromISR () for an alternative which may be used
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300 * @param xQueue The handle to the queue on which the item is to be posted.
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302 * @param pvItemToQueue A pointer to the item that is to be placed on the
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303 * queue. The size of the items the queue will hold was defined when the
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304 * queue was created, so this many bytes will be copied from pvItemToQueue
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305 * into the queue storage area.
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307 * @param xTicksToWait The maximum amount of time the task should block
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308 * waiting for space to become available on the queue, should it already
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309 * be full. The call will return immediately if this is set to 0 and the
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310 * queue is full. The time is defined in tick periods so the constant
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311 * portTICK_PERIOD_MS should be used to convert to real time if this is required.
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313 * @return pdTRUE if the item was successfully posted, otherwise errQUEUE_FULL.
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323 uint32_t ulVar = 10UL;
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325 void vATask( void *pvParameters )
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327 QueueHandle_t xQueue1, xQueue2;
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328 struct AMessage *pxMessage;
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330 // Create a queue capable of containing 10 uint32_t values.
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331 xQueue1 = xQueueCreate( 10, sizeof( uint32_t ) );
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333 // Create a queue capable of containing 10 pointers to AMessage structures.
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334 // These should be passed by pointer as they contain a lot of data.
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335 xQueue2 = xQueueCreate( 10, sizeof( struct AMessage * ) );
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341 // Send an uint32_t. Wait for 10 ticks for space to become
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342 // available if necessary.
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343 if( xQueueSendToFront( xQueue1, ( void * ) &ulVar, ( TickType_t ) 10 ) != pdPASS )
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345 // Failed to post the message, even after 10 ticks.
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351 // Send a pointer to a struct AMessage object. Don't block if the
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352 // queue is already full.
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353 pxMessage = & xMessage;
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354 xQueueSendToFront( xQueue2, ( void * ) &pxMessage, ( TickType_t ) 0 );
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357 // ... Rest of task code.
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360 * \defgroup xQueueSend xQueueSend
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361 * \ingroup QueueManagement
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363 #define xQueueSendToFront( xQueue, pvItemToQueue, xTicksToWait ) xQueueGenericSend( ( xQueue ), ( pvItemToQueue ), ( xTicksToWait ), queueSEND_TO_FRONT )
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368 BaseType_t xQueueSendToBack(
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369 QueueHandle_t xQueue,
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370 const void *pvItemToQueue,
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371 TickType_t xTicksToWait
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375 * This is a macro that calls xQueueGenericSend().
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377 * Post an item to the back of a queue. The item is queued by copy, not by
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378 * reference. This function must not be called from an interrupt service
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379 * routine. See xQueueSendFromISR () for an alternative which may be used
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382 * @param xQueue The handle to the queue on which the item is to be posted.
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384 * @param pvItemToQueue A pointer to the item that is to be placed on the
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385 * queue. The size of the items the queue will hold was defined when the
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386 * queue was created, so this many bytes will be copied from pvItemToQueue
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387 * into the queue storage area.
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389 * @param xTicksToWait The maximum amount of time the task should block
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390 * waiting for space to become available on the queue, should it already
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391 * be full. The call will return immediately if this is set to 0 and the queue
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392 * is full. The time is defined in tick periods so the constant
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393 * portTICK_PERIOD_MS should be used to convert to real time if this is required.
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395 * @return pdTRUE if the item was successfully posted, otherwise errQUEUE_FULL.
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405 uint32_t ulVar = 10UL;
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407 void vATask( void *pvParameters )
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409 QueueHandle_t xQueue1, xQueue2;
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410 struct AMessage *pxMessage;
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412 // Create a queue capable of containing 10 uint32_t values.
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413 xQueue1 = xQueueCreate( 10, sizeof( uint32_t ) );
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415 // Create a queue capable of containing 10 pointers to AMessage structures.
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416 // These should be passed by pointer as they contain a lot of data.
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417 xQueue2 = xQueueCreate( 10, sizeof( struct AMessage * ) );
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423 // Send an uint32_t. Wait for 10 ticks for space to become
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424 // available if necessary.
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425 if( xQueueSendToBack( xQueue1, ( void * ) &ulVar, ( TickType_t ) 10 ) != pdPASS )
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427 // Failed to post the message, even after 10 ticks.
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433 // Send a pointer to a struct AMessage object. Don't block if the
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434 // queue is already full.
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435 pxMessage = & xMessage;
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436 xQueueSendToBack( xQueue2, ( void * ) &pxMessage, ( TickType_t ) 0 );
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439 // ... Rest of task code.
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442 * \defgroup xQueueSend xQueueSend
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443 * \ingroup QueueManagement
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445 #define xQueueSendToBack( xQueue, pvItemToQueue, xTicksToWait ) xQueueGenericSend( ( xQueue ), ( pvItemToQueue ), ( xTicksToWait ), queueSEND_TO_BACK )
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450 BaseType_t xQueueSend(
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451 QueueHandle_t xQueue,
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452 const void * pvItemToQueue,
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453 TickType_t xTicksToWait
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457 * This is a macro that calls xQueueGenericSend(). It is included for
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458 * backward compatibility with versions of FreeRTOS.org that did not
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459 * include the xQueueSendToFront() and xQueueSendToBack() macros. It is
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460 * equivalent to xQueueSendToBack().
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462 * Post an item on a queue. The item is queued by copy, not by reference.
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463 * This function must not be called from an interrupt service routine.
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464 * See xQueueSendFromISR () for an alternative which may be used in an ISR.
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466 * @param xQueue The handle to the queue on which the item is to be posted.
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468 * @param pvItemToQueue A pointer to the item that is to be placed on the
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469 * queue. The size of the items the queue will hold was defined when the
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470 * queue was created, so this many bytes will be copied from pvItemToQueue
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471 * into the queue storage area.
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473 * @param xTicksToWait The maximum amount of time the task should block
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474 * waiting for space to become available on the queue, should it already
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475 * be full. The call will return immediately if this is set to 0 and the
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476 * queue is full. The time is defined in tick periods so the constant
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477 * portTICK_PERIOD_MS should be used to convert to real time if this is required.
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479 * @return pdTRUE if the item was successfully posted, otherwise errQUEUE_FULL.
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489 uint32_t ulVar = 10UL;
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491 void vATask( void *pvParameters )
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493 QueueHandle_t xQueue1, xQueue2;
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494 struct AMessage *pxMessage;
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496 // Create a queue capable of containing 10 uint32_t values.
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497 xQueue1 = xQueueCreate( 10, sizeof( uint32_t ) );
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499 // Create a queue capable of containing 10 pointers to AMessage structures.
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500 // These should be passed by pointer as they contain a lot of data.
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501 xQueue2 = xQueueCreate( 10, sizeof( struct AMessage * ) );
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507 // Send an uint32_t. Wait for 10 ticks for space to become
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508 // available if necessary.
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509 if( xQueueSend( xQueue1, ( void * ) &ulVar, ( TickType_t ) 10 ) != pdPASS )
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511 // Failed to post the message, even after 10 ticks.
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517 // Send a pointer to a struct AMessage object. Don't block if the
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518 // queue is already full.
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519 pxMessage = & xMessage;
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520 xQueueSend( xQueue2, ( void * ) &pxMessage, ( TickType_t ) 0 );
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523 // ... Rest of task code.
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526 * \defgroup xQueueSend xQueueSend
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527 * \ingroup QueueManagement
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529 #define xQueueSend( xQueue, pvItemToQueue, xTicksToWait ) xQueueGenericSend( ( xQueue ), ( pvItemToQueue ), ( xTicksToWait ), queueSEND_TO_BACK )
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534 BaseType_t xQueueOverwrite(
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535 QueueHandle_t xQueue,
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536 const void * pvItemToQueue
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540 * Only for use with queues that have a length of one - so the queue is either
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543 * Post an item on a queue. If the queue is already full then overwrite the
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544 * value held in the queue. The item is queued by copy, not by reference.
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546 * This function must not be called from an interrupt service routine.
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547 * See xQueueOverwriteFromISR () for an alternative which may be used in an ISR.
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549 * @param xQueue The handle of the queue to which the data is being sent.
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551 * @param pvItemToQueue A pointer to the item that is to be placed on the
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552 * queue. The size of the items the queue will hold was defined when the
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553 * queue was created, so this many bytes will be copied from pvItemToQueue
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554 * into the queue storage area.
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556 * @return xQueueOverwrite() is a macro that calls xQueueGenericSend(), and
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557 * therefore has the same return values as xQueueSendToFront(). However, pdPASS
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558 * is the only value that can be returned because xQueueOverwrite() will write
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559 * to the queue even when the queue is already full.
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564 void vFunction( void *pvParameters )
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566 QueueHandle_t xQueue;
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567 uint32_t ulVarToSend, ulValReceived;
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569 // Create a queue to hold one uint32_t value. It is strongly
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570 // recommended *not* to use xQueueOverwrite() on queues that can
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571 // contain more than one value, and doing so will trigger an assertion
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572 // if configASSERT() is defined.
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573 xQueue = xQueueCreate( 1, sizeof( uint32_t ) );
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575 // Write the value 10 to the queue using xQueueOverwrite().
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577 xQueueOverwrite( xQueue, &ulVarToSend );
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579 // Peeking the queue should now return 10, but leave the value 10 in
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580 // the queue. A block time of zero is used as it is known that the
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581 // queue holds a value.
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583 xQueuePeek( xQueue, &ulValReceived, 0 );
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585 if( ulValReceived != 10 )
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587 // Error unless the item was removed by a different task.
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590 // The queue is still full. Use xQueueOverwrite() to overwrite the
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591 // value held in the queue with 100.
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593 xQueueOverwrite( xQueue, &ulVarToSend );
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595 // This time read from the queue, leaving the queue empty once more.
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596 // A block time of 0 is used again.
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597 xQueueReceive( xQueue, &ulValReceived, 0 );
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599 // The value read should be the last value written, even though the
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600 // queue was already full when the value was written.
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601 if( ulValReceived != 100 )
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609 * \defgroup xQueueOverwrite xQueueOverwrite
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610 * \ingroup QueueManagement
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612 #define xQueueOverwrite( xQueue, pvItemToQueue ) xQueueGenericSend( ( xQueue ), ( pvItemToQueue ), 0, queueOVERWRITE )
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618 BaseType_t xQueueGenericSend(
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619 QueueHandle_t xQueue,
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620 const void * pvItemToQueue,
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621 TickType_t xTicksToWait
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622 BaseType_t xCopyPosition
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626 * It is preferred that the macros xQueueSend(), xQueueSendToFront() and
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627 * xQueueSendToBack() are used in place of calling this function directly.
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629 * Post an item on a queue. The item is queued by copy, not by reference.
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630 * This function must not be called from an interrupt service routine.
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631 * See xQueueSendFromISR () for an alternative which may be used in an ISR.
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633 * @param xQueue The handle to the queue on which the item is to be posted.
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635 * @param pvItemToQueue A pointer to the item that is to be placed on the
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636 * queue. The size of the items the queue will hold was defined when the
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637 * queue was created, so this many bytes will be copied from pvItemToQueue
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638 * into the queue storage area.
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640 * @param xTicksToWait The maximum amount of time the task should block
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641 * waiting for space to become available on the queue, should it already
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642 * be full. The call will return immediately if this is set to 0 and the
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643 * queue is full. The time is defined in tick periods so the constant
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644 * portTICK_PERIOD_MS should be used to convert to real time if this is required.
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646 * @param xCopyPosition Can take the value queueSEND_TO_BACK to place the
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647 * item at the back of the queue, or queueSEND_TO_FRONT to place the item
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648 * at the front of the queue (for high priority messages).
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650 * @return pdTRUE if the item was successfully posted, otherwise errQUEUE_FULL.
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660 uint32_t ulVar = 10UL;
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662 void vATask( void *pvParameters )
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664 QueueHandle_t xQueue1, xQueue2;
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665 struct AMessage *pxMessage;
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667 // Create a queue capable of containing 10 uint32_t values.
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668 xQueue1 = xQueueCreate( 10, sizeof( uint32_t ) );
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670 // Create a queue capable of containing 10 pointers to AMessage structures.
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671 // These should be passed by pointer as they contain a lot of data.
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672 xQueue2 = xQueueCreate( 10, sizeof( struct AMessage * ) );
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678 // Send an uint32_t. Wait for 10 ticks for space to become
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679 // available if necessary.
\r
680 if( xQueueGenericSend( xQueue1, ( void * ) &ulVar, ( TickType_t ) 10, queueSEND_TO_BACK ) != pdPASS )
\r
682 // Failed to post the message, even after 10 ticks.
\r
688 // Send a pointer to a struct AMessage object. Don't block if the
\r
689 // queue is already full.
\r
690 pxMessage = & xMessage;
\r
691 xQueueGenericSend( xQueue2, ( void * ) &pxMessage, ( TickType_t ) 0, queueSEND_TO_BACK );
\r
694 // ... Rest of task code.
\r
697 * \defgroup xQueueSend xQueueSend
\r
698 * \ingroup QueueManagement
\r
700 BaseType_t xQueueGenericSend( QueueHandle_t xQueue, const void * const pvItemToQueue, TickType_t xTicksToWait, const BaseType_t xCopyPosition ) PRIVILEGED_FUNCTION;
\r
705 BaseType_t xQueuePeek(
\r
706 QueueHandle_t xQueue,
\r
708 TickType_t xTicksToWait
\r
711 * This is a macro that calls the xQueueGenericReceive() function.
\r
713 * Receive an item from a queue without removing the item from the queue.
\r
714 * The item is received by copy so a buffer of adequate size must be
\r
715 * provided. The number of bytes copied into the buffer was defined when
\r
716 * the queue was created.
\r
718 * Successfully received items remain on the queue so will be returned again
\r
719 * by the next call, or a call to xQueueReceive().
\r
721 * This macro must not be used in an interrupt service routine. See
\r
722 * xQueuePeekFromISR() for an alternative that can be called from an interrupt
\r
725 * @param xQueue The handle to the queue from which the item is to be
\r
728 * @param pvBuffer Pointer to the buffer into which the received item will
\r
731 * @param xTicksToWait The maximum amount of time the task should block
\r
732 * waiting for an item to receive should the queue be empty at the time
\r
733 * of the call. The time is defined in tick periods so the constant
\r
734 * portTICK_PERIOD_MS should be used to convert to real time if this is required.
\r
735 * xQueuePeek() will return immediately if xTicksToWait is 0 and the queue
\r
738 * @return pdTRUE if an item was successfully received from the queue,
\r
739 * otherwise pdFALSE.
\r
749 QueueHandle_t xQueue;
\r
751 // Task to create a queue and post a value.
\r
752 void vATask( void *pvParameters )
\r
754 struct AMessage *pxMessage;
\r
756 // Create a queue capable of containing 10 pointers to AMessage structures.
\r
757 // These should be passed by pointer as they contain a lot of data.
\r
758 xQueue = xQueueCreate( 10, sizeof( struct AMessage * ) );
\r
761 // Failed to create the queue.
\r
766 // Send a pointer to a struct AMessage object. Don't block if the
\r
767 // queue is already full.
\r
768 pxMessage = & xMessage;
\r
769 xQueueSend( xQueue, ( void * ) &pxMessage, ( TickType_t ) 0 );
\r
771 // ... Rest of task code.
\r
774 // Task to peek the data from the queue.
\r
775 void vADifferentTask( void *pvParameters )
\r
777 struct AMessage *pxRxedMessage;
\r
781 // Peek a message on the created queue. Block for 10 ticks if a
\r
782 // message is not immediately available.
\r
783 if( xQueuePeek( xQueue, &( pxRxedMessage ), ( TickType_t ) 10 ) )
\r
785 // pcRxedMessage now points to the struct AMessage variable posted
\r
786 // by vATask, but the item still remains on the queue.
\r
790 // ... Rest of task code.
\r
793 * \defgroup xQueueReceive xQueueReceive
\r
794 * \ingroup QueueManagement
\r
796 #define xQueuePeek( xQueue, pvBuffer, xTicksToWait ) xQueueGenericReceive( ( xQueue ), ( pvBuffer ), ( xTicksToWait ), pdTRUE )
\r
801 BaseType_t xQueuePeekFromISR(
\r
802 QueueHandle_t xQueue,
\r
806 * A version of xQueuePeek() that can be called from an interrupt service
\r
809 * Receive an item from a queue without removing the item from the queue.
\r
810 * The item is received by copy so a buffer of adequate size must be
\r
811 * provided. The number of bytes copied into the buffer was defined when
\r
812 * the queue was created.
\r
814 * Successfully received items remain on the queue so will be returned again
\r
815 * by the next call, or a call to xQueueReceive().
\r
817 * @param xQueue The handle to the queue from which the item is to be
\r
820 * @param pvBuffer Pointer to the buffer into which the received item will
\r
823 * @return pdTRUE if an item was successfully received from the queue,
\r
824 * otherwise pdFALSE.
\r
826 * \defgroup xQueuePeekFromISR xQueuePeekFromISR
\r
827 * \ingroup QueueManagement
\r
829 BaseType_t xQueuePeekFromISR( QueueHandle_t xQueue, void * const pvBuffer ) PRIVILEGED_FUNCTION;
\r
834 BaseType_t xQueueReceive(
\r
835 QueueHandle_t xQueue,
\r
837 TickType_t xTicksToWait
\r
840 * This is a macro that calls the xQueueGenericReceive() function.
\r
842 * Receive an item from a queue. The item is received by copy so a buffer of
\r
843 * adequate size must be provided. The number of bytes copied into the buffer
\r
844 * was defined when the queue was created.
\r
846 * Successfully received items are removed from the queue.
\r
848 * This function must not be used in an interrupt service routine. See
\r
849 * xQueueReceiveFromISR for an alternative that can.
\r
851 * @param xQueue The handle to the queue from which the item is to be
\r
854 * @param pvBuffer Pointer to the buffer into which the received item will
\r
857 * @param xTicksToWait The maximum amount of time the task should block
\r
858 * waiting for an item to receive should the queue be empty at the time
\r
859 * of the call. xQueueReceive() will return immediately if xTicksToWait
\r
860 * is zero and the queue is empty. The time is defined in tick periods so the
\r
861 * constant portTICK_PERIOD_MS should be used to convert to real time if this is
\r
864 * @return pdTRUE if an item was successfully received from the queue,
\r
865 * otherwise pdFALSE.
\r
875 QueueHandle_t xQueue;
\r
877 // Task to create a queue and post a value.
\r
878 void vATask( void *pvParameters )
\r
880 struct AMessage *pxMessage;
\r
882 // Create a queue capable of containing 10 pointers to AMessage structures.
\r
883 // These should be passed by pointer as they contain a lot of data.
\r
884 xQueue = xQueueCreate( 10, sizeof( struct AMessage * ) );
\r
887 // Failed to create the queue.
\r
892 // Send a pointer to a struct AMessage object. Don't block if the
\r
893 // queue is already full.
\r
894 pxMessage = & xMessage;
\r
895 xQueueSend( xQueue, ( void * ) &pxMessage, ( TickType_t ) 0 );
\r
897 // ... Rest of task code.
\r
900 // Task to receive from the queue.
\r
901 void vADifferentTask( void *pvParameters )
\r
903 struct AMessage *pxRxedMessage;
\r
907 // Receive a message on the created queue. Block for 10 ticks if a
\r
908 // message is not immediately available.
\r
909 if( xQueueReceive( xQueue, &( pxRxedMessage ), ( TickType_t ) 10 ) )
\r
911 // pcRxedMessage now points to the struct AMessage variable posted
\r
916 // ... Rest of task code.
\r
919 * \defgroup xQueueReceive xQueueReceive
\r
920 * \ingroup QueueManagement
\r
922 #define xQueueReceive( xQueue, pvBuffer, xTicksToWait ) xQueueGenericReceive( ( xQueue ), ( pvBuffer ), ( xTicksToWait ), pdFALSE )
\r
928 BaseType_t xQueueGenericReceive(
\r
929 QueueHandle_t xQueue,
\r
931 TickType_t xTicksToWait
\r
932 BaseType_t xJustPeek
\r
935 * It is preferred that the macro xQueueReceive() be used rather than calling
\r
936 * this function directly.
\r
938 * Receive an item from a queue. The item is received by copy so a buffer of
\r
939 * adequate size must be provided. The number of bytes copied into the buffer
\r
940 * was defined when the queue was created.
\r
942 * This function must not be used in an interrupt service routine. See
\r
943 * xQueueReceiveFromISR for an alternative that can.
\r
945 * @param xQueue The handle to the queue from which the item is to be
\r
948 * @param pvBuffer Pointer to the buffer into which the received item will
\r
951 * @param xTicksToWait The maximum amount of time the task should block
\r
952 * waiting for an item to receive should the queue be empty at the time
\r
953 * of the call. The time is defined in tick periods so the constant
\r
954 * portTICK_PERIOD_MS should be used to convert to real time if this is required.
\r
955 * xQueueGenericReceive() will return immediately if the queue is empty and
\r
956 * xTicksToWait is 0.
\r
958 * @param xJustPeek When set to true, the item received from the queue is not
\r
959 * actually removed from the queue - meaning a subsequent call to
\r
960 * xQueueReceive() will return the same item. When set to false, the item
\r
961 * being received from the queue is also removed from the queue.
\r
963 * @return pdTRUE if an item was successfully received from the queue,
\r
964 * otherwise pdFALSE.
\r
974 QueueHandle_t xQueue;
\r
976 // Task to create a queue and post a value.
\r
977 void vATask( void *pvParameters )
\r
979 struct AMessage *pxMessage;
\r
981 // Create a queue capable of containing 10 pointers to AMessage structures.
\r
982 // These should be passed by pointer as they contain a lot of data.
\r
983 xQueue = xQueueCreate( 10, sizeof( struct AMessage * ) );
\r
986 // Failed to create the queue.
\r
991 // Send a pointer to a struct AMessage object. Don't block if the
\r
992 // queue is already full.
\r
993 pxMessage = & xMessage;
\r
994 xQueueSend( xQueue, ( void * ) &pxMessage, ( TickType_t ) 0 );
\r
996 // ... Rest of task code.
\r
999 // Task to receive from the queue.
\r
1000 void vADifferentTask( void *pvParameters )
\r
1002 struct AMessage *pxRxedMessage;
\r
1006 // Receive a message on the created queue. Block for 10 ticks if a
\r
1007 // message is not immediately available.
\r
1008 if( xQueueGenericReceive( xQueue, &( pxRxedMessage ), ( TickType_t ) 10 ) )
\r
1010 // pcRxedMessage now points to the struct AMessage variable posted
\r
1015 // ... Rest of task code.
\r
1018 * \defgroup xQueueReceive xQueueReceive
\r
1019 * \ingroup QueueManagement
\r
1021 BaseType_t xQueueGenericReceive( QueueHandle_t xQueue, void * const pvBuffer, TickType_t xTicksToWait, const BaseType_t xJustPeek ) PRIVILEGED_FUNCTION;
\r
1025 * <pre>UBaseType_t uxQueueMessagesWaiting( const QueueHandle_t xQueue );</pre>
\r
1027 * Return the number of messages stored in a queue.
\r
1029 * @param xQueue A handle to the queue being queried.
\r
1031 * @return The number of messages available in the queue.
\r
1033 * \defgroup uxQueueMessagesWaiting uxQueueMessagesWaiting
\r
1034 * \ingroup QueueManagement
\r
1036 UBaseType_t uxQueueMessagesWaiting( const QueueHandle_t xQueue ) PRIVILEGED_FUNCTION;
\r
1040 * <pre>UBaseType_t uxQueueSpacesAvailable( const QueueHandle_t xQueue );</pre>
\r
1042 * Return the number of free spaces available in a queue. This is equal to the
\r
1043 * number of items that can be sent to the queue before the queue becomes full
\r
1044 * if no items are removed.
\r
1046 * @param xQueue A handle to the queue being queried.
\r
1048 * @return The number of spaces available in the queue.
\r
1050 * \defgroup uxQueueMessagesWaiting uxQueueMessagesWaiting
\r
1051 * \ingroup QueueManagement
\r
1053 UBaseType_t uxQueueSpacesAvailable( const QueueHandle_t xQueue ) PRIVILEGED_FUNCTION;
\r
1057 * <pre>void vQueueDelete( QueueHandle_t xQueue );</pre>
\r
1059 * Delete a queue - freeing all the memory allocated for storing of items
\r
1060 * placed on the queue.
\r
1062 * @param xQueue A handle to the queue to be deleted.
\r
1064 * \defgroup vQueueDelete vQueueDelete
\r
1065 * \ingroup QueueManagement
\r
1067 void vQueueDelete( QueueHandle_t xQueue ) PRIVILEGED_FUNCTION;
\r
1072 BaseType_t xQueueSendToFrontFromISR(
\r
1073 QueueHandle_t xQueue,
\r
1074 const void *pvItemToQueue,
\r
1075 BaseType_t *pxHigherPriorityTaskWoken
\r
1079 * This is a macro that calls xQueueGenericSendFromISR().
\r
1081 * Post an item to the front of a queue. It is safe to use this macro from
\r
1082 * within an interrupt service routine.
\r
1084 * Items are queued by copy not reference so it is preferable to only
\r
1085 * queue small items, especially when called from an ISR. In most cases
\r
1086 * it would be preferable to store a pointer to the item being queued.
\r
1088 * @param xQueue The handle to the queue on which the item is to be posted.
\r
1090 * @param pvItemToQueue A pointer to the item that is to be placed on the
\r
1091 * queue. The size of the items the queue will hold was defined when the
\r
1092 * queue was created, so this many bytes will be copied from pvItemToQueue
\r
1093 * into the queue storage area.
\r
1095 * @param pxHigherPriorityTaskWoken xQueueSendToFrontFromISR() will set
\r
1096 * *pxHigherPriorityTaskWoken to pdTRUE if sending to the queue caused a task
\r
1097 * to unblock, and the unblocked task has a priority higher than the currently
\r
1098 * running task. If xQueueSendToFromFromISR() sets this value to pdTRUE then
\r
1099 * a context switch should be requested before the interrupt is exited.
\r
1101 * @return pdTRUE if the data was successfully sent to the queue, otherwise
\r
1104 * Example usage for buffered IO (where the ISR can obtain more than one value
\r
1107 void vBufferISR( void )
\r
1110 BaseType_t xHigherPrioritTaskWoken;
\r
1112 // We have not woken a task at the start of the ISR.
\r
1113 xHigherPriorityTaskWoken = pdFALSE;
\r
1115 // Loop until the buffer is empty.
\r
1118 // Obtain a byte from the buffer.
\r
1119 cIn = portINPUT_BYTE( RX_REGISTER_ADDRESS );
\r
1122 xQueueSendToFrontFromISR( xRxQueue, &cIn, &xHigherPriorityTaskWoken );
\r
1124 } while( portINPUT_BYTE( BUFFER_COUNT ) );
\r
1126 // Now the buffer is empty we can switch context if necessary.
\r
1127 if( xHigherPriorityTaskWoken )
\r
1134 * \defgroup xQueueSendFromISR xQueueSendFromISR
\r
1135 * \ingroup QueueManagement
\r
1137 #define xQueueSendToFrontFromISR( xQueue, pvItemToQueue, pxHigherPriorityTaskWoken ) xQueueGenericSendFromISR( ( xQueue ), ( pvItemToQueue ), ( pxHigherPriorityTaskWoken ), queueSEND_TO_FRONT )
\r
1143 BaseType_t xQueueSendToBackFromISR(
\r
1144 QueueHandle_t xQueue,
\r
1145 const void *pvItemToQueue,
\r
1146 BaseType_t *pxHigherPriorityTaskWoken
\r
1150 * This is a macro that calls xQueueGenericSendFromISR().
\r
1152 * Post an item to the back of a queue. It is safe to use this macro from
\r
1153 * within an interrupt service routine.
\r
1155 * Items are queued by copy not reference so it is preferable to only
\r
1156 * queue small items, especially when called from an ISR. In most cases
\r
1157 * it would be preferable to store a pointer to the item being queued.
\r
1159 * @param xQueue The handle to the queue on which the item is to be posted.
\r
1161 * @param pvItemToQueue A pointer to the item that is to be placed on the
\r
1162 * queue. The size of the items the queue will hold was defined when the
\r
1163 * queue was created, so this many bytes will be copied from pvItemToQueue
\r
1164 * into the queue storage area.
\r
1166 * @param pxHigherPriorityTaskWoken xQueueSendToBackFromISR() will set
\r
1167 * *pxHigherPriorityTaskWoken to pdTRUE if sending to the queue caused a task
\r
1168 * to unblock, and the unblocked task has a priority higher than the currently
\r
1169 * running task. If xQueueSendToBackFromISR() sets this value to pdTRUE then
\r
1170 * a context switch should be requested before the interrupt is exited.
\r
1172 * @return pdTRUE if the data was successfully sent to the queue, otherwise
\r
1175 * Example usage for buffered IO (where the ISR can obtain more than one value
\r
1178 void vBufferISR( void )
\r
1181 BaseType_t xHigherPriorityTaskWoken;
\r
1183 // We have not woken a task at the start of the ISR.
\r
1184 xHigherPriorityTaskWoken = pdFALSE;
\r
1186 // Loop until the buffer is empty.
\r
1189 // Obtain a byte from the buffer.
\r
1190 cIn = portINPUT_BYTE( RX_REGISTER_ADDRESS );
\r
1193 xQueueSendToBackFromISR( xRxQueue, &cIn, &xHigherPriorityTaskWoken );
\r
1195 } while( portINPUT_BYTE( BUFFER_COUNT ) );
\r
1197 // Now the buffer is empty we can switch context if necessary.
\r
1198 if( xHigherPriorityTaskWoken )
\r
1205 * \defgroup xQueueSendFromISR xQueueSendFromISR
\r
1206 * \ingroup QueueManagement
\r
1208 #define xQueueSendToBackFromISR( xQueue, pvItemToQueue, pxHigherPriorityTaskWoken ) xQueueGenericSendFromISR( ( xQueue ), ( pvItemToQueue ), ( pxHigherPriorityTaskWoken ), queueSEND_TO_BACK )
\r
1213 BaseType_t xQueueOverwriteFromISR(
\r
1214 QueueHandle_t xQueue,
\r
1215 const void * pvItemToQueue,
\r
1216 BaseType_t *pxHigherPriorityTaskWoken
\r
1220 * A version of xQueueOverwrite() that can be used in an interrupt service
\r
1223 * Only for use with queues that can hold a single item - so the queue is either
\r
1226 * Post an item on a queue. If the queue is already full then overwrite the
\r
1227 * value held in the queue. The item is queued by copy, not by reference.
\r
1229 * @param xQueue The handle to the queue on which the item is to be posted.
\r
1231 * @param pvItemToQueue A pointer to the item that is to be placed on the
\r
1232 * queue. The size of the items the queue will hold was defined when the
\r
1233 * queue was created, so this many bytes will be copied from pvItemToQueue
\r
1234 * into the queue storage area.
\r
1236 * @param pxHigherPriorityTaskWoken xQueueOverwriteFromISR() will set
\r
1237 * *pxHigherPriorityTaskWoken to pdTRUE if sending to the queue caused a task
\r
1238 * to unblock, and the unblocked task has a priority higher than the currently
\r
1239 * running task. If xQueueOverwriteFromISR() sets this value to pdTRUE then
\r
1240 * a context switch should be requested before the interrupt is exited.
\r
1242 * @return xQueueOverwriteFromISR() is a macro that calls
\r
1243 * xQueueGenericSendFromISR(), and therefore has the same return values as
\r
1244 * xQueueSendToFrontFromISR(). However, pdPASS is the only value that can be
\r
1245 * returned because xQueueOverwriteFromISR() will write to the queue even when
\r
1246 * the queue is already full.
\r
1251 QueueHandle_t xQueue;
\r
1253 void vFunction( void *pvParameters )
\r
1255 // Create a queue to hold one uint32_t value. It is strongly
\r
1256 // recommended *not* to use xQueueOverwriteFromISR() on queues that can
\r
1257 // contain more than one value, and doing so will trigger an assertion
\r
1258 // if configASSERT() is defined.
\r
1259 xQueue = xQueueCreate( 1, sizeof( uint32_t ) );
\r
1262 void vAnInterruptHandler( void )
\r
1264 // xHigherPriorityTaskWoken must be set to pdFALSE before it is used.
\r
1265 BaseType_t xHigherPriorityTaskWoken = pdFALSE;
\r
1266 uint32_t ulVarToSend, ulValReceived;
\r
1268 // Write the value 10 to the queue using xQueueOverwriteFromISR().
\r
1270 xQueueOverwriteFromISR( xQueue, &ulVarToSend, &xHigherPriorityTaskWoken );
\r
1272 // The queue is full, but calling xQueueOverwriteFromISR() again will still
\r
1273 // pass because the value held in the queue will be overwritten with the
\r
1275 ulVarToSend = 100;
\r
1276 xQueueOverwriteFromISR( xQueue, &ulVarToSend, &xHigherPriorityTaskWoken );
\r
1278 // Reading from the queue will now return 100.
\r
1282 if( xHigherPrioritytaskWoken == pdTRUE )
\r
1284 // Writing to the queue caused a task to unblock and the unblocked task
\r
1285 // has a priority higher than or equal to the priority of the currently
\r
1286 // executing task (the task this interrupt interrupted). Perform a context
\r
1287 // switch so this interrupt returns directly to the unblocked task.
\r
1288 portYIELD_FROM_ISR(); // or portEND_SWITCHING_ISR() depending on the port.
\r
1292 * \defgroup xQueueOverwriteFromISR xQueueOverwriteFromISR
\r
1293 * \ingroup QueueManagement
\r
1295 #define xQueueOverwriteFromISR( xQueue, pvItemToQueue, pxHigherPriorityTaskWoken ) xQueueGenericSendFromISR( ( xQueue ), ( pvItemToQueue ), ( pxHigherPriorityTaskWoken ), queueOVERWRITE )
\r
1300 BaseType_t xQueueSendFromISR(
\r
1301 QueueHandle_t xQueue,
\r
1302 const void *pvItemToQueue,
\r
1303 BaseType_t *pxHigherPriorityTaskWoken
\r
1307 * This is a macro that calls xQueueGenericSendFromISR(). It is included
\r
1308 * for backward compatibility with versions of FreeRTOS.org that did not
\r
1309 * include the xQueueSendToBackFromISR() and xQueueSendToFrontFromISR()
\r
1312 * Post an item to the back of a queue. It is safe to use this function from
\r
1313 * within an interrupt service routine.
\r
1315 * Items are queued by copy not reference so it is preferable to only
\r
1316 * queue small items, especially when called from an ISR. In most cases
\r
1317 * it would be preferable to store a pointer to the item being queued.
\r
1319 * @param xQueue The handle to the queue on which the item is to be posted.
\r
1321 * @param pvItemToQueue A pointer to the item that is to be placed on the
\r
1322 * queue. The size of the items the queue will hold was defined when the
\r
1323 * queue was created, so this many bytes will be copied from pvItemToQueue
\r
1324 * into the queue storage area.
\r
1326 * @param pxHigherPriorityTaskWoken xQueueSendFromISR() will set
\r
1327 * *pxHigherPriorityTaskWoken to pdTRUE if sending to the queue caused a task
\r
1328 * to unblock, and the unblocked task has a priority higher than the currently
\r
1329 * running task. If xQueueSendFromISR() sets this value to pdTRUE then
\r
1330 * a context switch should be requested before the interrupt is exited.
\r
1332 * @return pdTRUE if the data was successfully sent to the queue, otherwise
\r
1335 * Example usage for buffered IO (where the ISR can obtain more than one value
\r
1338 void vBufferISR( void )
\r
1341 BaseType_t xHigherPriorityTaskWoken;
\r
1343 // We have not woken a task at the start of the ISR.
\r
1344 xHigherPriorityTaskWoken = pdFALSE;
\r
1346 // Loop until the buffer is empty.
\r
1349 // Obtain a byte from the buffer.
\r
1350 cIn = portINPUT_BYTE( RX_REGISTER_ADDRESS );
\r
1353 xQueueSendFromISR( xRxQueue, &cIn, &xHigherPriorityTaskWoken );
\r
1355 } while( portINPUT_BYTE( BUFFER_COUNT ) );
\r
1357 // Now the buffer is empty we can switch context if necessary.
\r
1358 if( xHigherPriorityTaskWoken )
\r
1360 // Actual macro used here is port specific.
\r
1361 portYIELD_FROM_ISR ();
\r
1366 * \defgroup xQueueSendFromISR xQueueSendFromISR
\r
1367 * \ingroup QueueManagement
\r
1369 #define xQueueSendFromISR( xQueue, pvItemToQueue, pxHigherPriorityTaskWoken ) xQueueGenericSendFromISR( ( xQueue ), ( pvItemToQueue ), ( pxHigherPriorityTaskWoken ), queueSEND_TO_BACK )
\r
1374 BaseType_t xQueueGenericSendFromISR(
\r
1375 QueueHandle_t xQueue,
\r
1376 const void *pvItemToQueue,
\r
1377 BaseType_t *pxHigherPriorityTaskWoken,
\r
1378 BaseType_t xCopyPosition
\r
1382 * It is preferred that the macros xQueueSendFromISR(),
\r
1383 * xQueueSendToFrontFromISR() and xQueueSendToBackFromISR() be used in place
\r
1384 * of calling this function directly. xQueueGiveFromISR() is an
\r
1385 * equivalent for use by semaphores that don't actually copy any data.
\r
1387 * Post an item on a queue. It is safe to use this function from within an
\r
1388 * interrupt service routine.
\r
1390 * Items are queued by copy not reference so it is preferable to only
\r
1391 * queue small items, especially when called from an ISR. In most cases
\r
1392 * it would be preferable to store a pointer to the item being queued.
\r
1394 * @param xQueue The handle to the queue on which the item is to be posted.
\r
1396 * @param pvItemToQueue A pointer to the item that is to be placed on the
\r
1397 * queue. The size of the items the queue will hold was defined when the
\r
1398 * queue was created, so this many bytes will be copied from pvItemToQueue
\r
1399 * into the queue storage area.
\r
1401 * @param pxHigherPriorityTaskWoken xQueueGenericSendFromISR() will set
\r
1402 * *pxHigherPriorityTaskWoken to pdTRUE if sending to the queue caused a task
\r
1403 * to unblock, and the unblocked task has a priority higher than the currently
\r
1404 * running task. If xQueueGenericSendFromISR() sets this value to pdTRUE then
\r
1405 * a context switch should be requested before the interrupt is exited.
\r
1407 * @param xCopyPosition Can take the value queueSEND_TO_BACK to place the
\r
1408 * item at the back of the queue, or queueSEND_TO_FRONT to place the item
\r
1409 * at the front of the queue (for high priority messages).
\r
1411 * @return pdTRUE if the data was successfully sent to the queue, otherwise
\r
1414 * Example usage for buffered IO (where the ISR can obtain more than one value
\r
1417 void vBufferISR( void )
\r
1420 BaseType_t xHigherPriorityTaskWokenByPost;
\r
1422 // We have not woken a task at the start of the ISR.
\r
1423 xHigherPriorityTaskWokenByPost = pdFALSE;
\r
1425 // Loop until the buffer is empty.
\r
1428 // Obtain a byte from the buffer.
\r
1429 cIn = portINPUT_BYTE( RX_REGISTER_ADDRESS );
\r
1431 // Post each byte.
\r
1432 xQueueGenericSendFromISR( xRxQueue, &cIn, &xHigherPriorityTaskWokenByPost, queueSEND_TO_BACK );
\r
1434 } while( portINPUT_BYTE( BUFFER_COUNT ) );
\r
1436 // Now the buffer is empty we can switch context if necessary. Note that the
\r
1437 // name of the yield function required is port specific.
\r
1438 if( xHigherPriorityTaskWokenByPost )
\r
1440 taskYIELD_YIELD_FROM_ISR();
\r
1445 * \defgroup xQueueSendFromISR xQueueSendFromISR
\r
1446 * \ingroup QueueManagement
\r
1448 BaseType_t xQueueGenericSendFromISR( QueueHandle_t xQueue, const void * const pvItemToQueue, BaseType_t * const pxHigherPriorityTaskWoken, const BaseType_t xCopyPosition ) PRIVILEGED_FUNCTION;
\r
1449 BaseType_t xQueueGiveFromISR( QueueHandle_t xQueue, BaseType_t * const pxHigherPriorityTaskWoken ) PRIVILEGED_FUNCTION;
\r
1454 BaseType_t xQueueReceiveFromISR(
\r
1455 QueueHandle_t xQueue,
\r
1457 BaseType_t *pxTaskWoken
\r
1461 * Receive an item from a queue. It is safe to use this function from within an
\r
1462 * interrupt service routine.
\r
1464 * @param xQueue The handle to the queue from which the item is to be
\r
1467 * @param pvBuffer Pointer to the buffer into which the received item will
\r
1470 * @param pxTaskWoken A task may be blocked waiting for space to become
\r
1471 * available on the queue. If xQueueReceiveFromISR causes such a task to
\r
1472 * unblock *pxTaskWoken will get set to pdTRUE, otherwise *pxTaskWoken will
\r
1473 * remain unchanged.
\r
1475 * @return pdTRUE if an item was successfully received from the queue,
\r
1476 * otherwise pdFALSE.
\r
1481 QueueHandle_t xQueue;
\r
1483 // Function to create a queue and post some values.
\r
1484 void vAFunction( void *pvParameters )
\r
1486 char cValueToPost;
\r
1487 const TickType_t xTicksToWait = ( TickType_t )0xff;
\r
1489 // Create a queue capable of containing 10 characters.
\r
1490 xQueue = xQueueCreate( 10, sizeof( char ) );
\r
1493 // Failed to create the queue.
\r
1498 // Post some characters that will be used within an ISR. If the queue
\r
1499 // is full then this task will block for xTicksToWait ticks.
\r
1500 cValueToPost = 'a';
\r
1501 xQueueSend( xQueue, ( void * ) &cValueToPost, xTicksToWait );
\r
1502 cValueToPost = 'b';
\r
1503 xQueueSend( xQueue, ( void * ) &cValueToPost, xTicksToWait );
\r
1505 // ... keep posting characters ... this task may block when the queue
\r
1508 cValueToPost = 'c';
\r
1509 xQueueSend( xQueue, ( void * ) &cValueToPost, xTicksToWait );
\r
1512 // ISR that outputs all the characters received on the queue.
\r
1513 void vISR_Routine( void )
\r
1515 BaseType_t xTaskWokenByReceive = pdFALSE;
\r
1518 while( xQueueReceiveFromISR( xQueue, ( void * ) &cRxedChar, &xTaskWokenByReceive) )
\r
1520 // A character was received. Output the character now.
\r
1521 vOutputCharacter( cRxedChar );
\r
1523 // If removing the character from the queue woke the task that was
\r
1524 // posting onto the queue cTaskWokenByReceive will have been set to
\r
1525 // pdTRUE. No matter how many times this loop iterates only one
\r
1526 // task will be woken.
\r
1529 if( cTaskWokenByPost != ( char ) pdFALSE;
\r
1535 * \defgroup xQueueReceiveFromISR xQueueReceiveFromISR
\r
1536 * \ingroup QueueManagement
\r
1538 BaseType_t xQueueReceiveFromISR( QueueHandle_t xQueue, void * const pvBuffer, BaseType_t * const pxHigherPriorityTaskWoken ) PRIVILEGED_FUNCTION;
\r
1541 * Utilities to query queues that are safe to use from an ISR. These utilities
\r
1542 * should be used only from witin an ISR, or within a critical section.
\r
1544 BaseType_t xQueueIsQueueEmptyFromISR( const QueueHandle_t xQueue ) PRIVILEGED_FUNCTION;
\r
1545 BaseType_t xQueueIsQueueFullFromISR( const QueueHandle_t xQueue ) PRIVILEGED_FUNCTION;
\r
1546 UBaseType_t uxQueueMessagesWaitingFromISR( const QueueHandle_t xQueue ) PRIVILEGED_FUNCTION;
\r
1549 * The functions defined above are for passing data to and from tasks. The
\r
1550 * functions below are the equivalents for passing data to and from
\r
1553 * These functions are called from the co-routine macro implementation and
\r
1554 * should not be called directly from application code. Instead use the macro
\r
1555 * wrappers defined within croutine.h.
\r
1557 BaseType_t xQueueCRSendFromISR( QueueHandle_t xQueue, const void *pvItemToQueue, BaseType_t xCoRoutinePreviouslyWoken );
\r
1558 BaseType_t xQueueCRReceiveFromISR( QueueHandle_t xQueue, void *pvBuffer, BaseType_t *pxTaskWoken );
\r
1559 BaseType_t xQueueCRSend( QueueHandle_t xQueue, const void *pvItemToQueue, TickType_t xTicksToWait );
\r
1560 BaseType_t xQueueCRReceive( QueueHandle_t xQueue, void *pvBuffer, TickType_t xTicksToWait );
\r
1563 * For internal use only. Use xSemaphoreCreateMutex(),
\r
1564 * xSemaphoreCreateCounting() or xSemaphoreGetMutexHolder() instead of calling
\r
1565 * these functions directly.
\r
1567 QueueHandle_t xQueueCreateMutex( const uint8_t ucQueueType ) PRIVILEGED_FUNCTION;
\r
1568 QueueHandle_t xQueueCreateMutexStatic( const uint8_t ucQueueType, StaticQueue_t *pxStaticQueue ) PRIVILEGED_FUNCTION;
\r
1569 QueueHandle_t xQueueCreateCountingSemaphore( const UBaseType_t uxMaxCount, const UBaseType_t uxInitialCount ) PRIVILEGED_FUNCTION;
\r
1570 QueueHandle_t xQueueCreateCountingSemaphoreStatic( const UBaseType_t uxMaxCount, const UBaseType_t uxInitialCount, StaticQueue_t *pxStaticQueue ) PRIVILEGED_FUNCTION;
\r
1571 void* xQueueGetMutexHolder( QueueHandle_t xSemaphore ) PRIVILEGED_FUNCTION;
\r
1574 * For internal use only. Use xSemaphoreTakeMutexRecursive() or
\r
1575 * xSemaphoreGiveMutexRecursive() instead of calling these functions directly.
\r
1577 BaseType_t xQueueTakeMutexRecursive( QueueHandle_t xMutex, TickType_t xTicksToWait ) PRIVILEGED_FUNCTION;
\r
1578 BaseType_t xQueueGiveMutexRecursive( QueueHandle_t pxMutex ) PRIVILEGED_FUNCTION;
\r
1581 * Reset a queue back to its original empty state. The return value is now
\r
1582 * obsolete and is always set to pdPASS.
\r
1584 #define xQueueReset( xQueue ) xQueueGenericReset( xQueue, pdFALSE )
\r
1587 * The registry is provided as a means for kernel aware debuggers to
\r
1588 * locate queues, semaphores and mutexes. Call vQueueAddToRegistry() add
\r
1589 * a queue, semaphore or mutex handle to the registry if you want the handle
\r
1590 * to be available to a kernel aware debugger. If you are not using a kernel
\r
1591 * aware debugger then this function can be ignored.
\r
1593 * configQUEUE_REGISTRY_SIZE defines the maximum number of handles the
\r
1594 * registry can hold. configQUEUE_REGISTRY_SIZE must be greater than 0
\r
1595 * within FreeRTOSConfig.h for the registry to be available. Its value
\r
1596 * does not effect the number of queues, semaphores and mutexes that can be
\r
1597 * created - just the number that the registry can hold.
\r
1599 * @param xQueue The handle of the queue being added to the registry. This
\r
1600 * is the handle returned by a call to xQueueCreate(). Semaphore and mutex
\r
1601 * handles can also be passed in here.
\r
1603 * @param pcName The name to be associated with the handle. This is the
\r
1604 * name that the kernel aware debugger will display. The queue registry only
\r
1605 * stores a pointer to the string - so the string must be persistent (global or
\r
1606 * preferably in ROM/Flash), not on the stack.
\r
1608 #if( configQUEUE_REGISTRY_SIZE > 0 )
\r
1609 void vQueueAddToRegistry( QueueHandle_t xQueue, const char *pcName ) PRIVILEGED_FUNCTION; /*lint !e971 Unqualified char types are allowed for strings and single characters only. */
\r
1613 * The registry is provided as a means for kernel aware debuggers to
\r
1614 * locate queues, semaphores and mutexes. Call vQueueAddToRegistry() add
\r
1615 * a queue, semaphore or mutex handle to the registry if you want the handle
\r
1616 * to be available to a kernel aware debugger, and vQueueUnregisterQueue() to
\r
1617 * remove the queue, semaphore or mutex from the register. If you are not using
\r
1618 * a kernel aware debugger then this function can be ignored.
\r
1620 * @param xQueue The handle of the queue being removed from the registry.
\r
1622 #if( configQUEUE_REGISTRY_SIZE > 0 )
\r
1623 void vQueueUnregisterQueue( QueueHandle_t xQueue ) PRIVILEGED_FUNCTION;
\r
1627 * The registry is provided as a means for kernel aware debuggers to
\r
1628 * locate queues, semaphores and mutexes. Call pcQueueGetQueueName() to look
\r
1629 * up and return the name of a queue in the queue registry from the queue's
\r
1632 * @param xQueue The handle of the queue the name of which will be returned.
\r
1633 * @return If the queue is in the registry then a pointer to the name of the
\r
1634 * queue is returned. If the queue is not in the registry then NULL is
\r
1637 #if( configQUEUE_REGISTRY_SIZE > 0 )
\r
1638 const char *pcQueueGetQueueName( QueueHandle_t xQueue ) PRIVILEGED_FUNCTION; /*lint !e971 Unqualified char types are allowed for strings and single characters only. */
\r
1642 * Generic version of the function used to creaet a queue using dynamic memory
\r
1643 * allocation. This is called by other functions and macros that create other
\r
1644 * RTOS objects that use the queue structure as their base.
\r
1646 #if( configSUPPORT_DYNAMIC_ALLOCATION == 1 )
\r
1647 QueueHandle_t xQueueGenericCreate( const UBaseType_t uxQueueLength, const UBaseType_t uxItemSize, const uint8_t ucQueueType ) PRIVILEGED_FUNCTION;
\r
1651 * Generic version of the function used to creaet a queue using dynamic memory
\r
1652 * allocation. This is called by other functions and macros that create other
\r
1653 * RTOS objects that use the queue structure as their base.
\r
1655 #if( configSUPPORT_STATIC_ALLOCATION == 1 )
\r
1656 QueueHandle_t xQueueGenericCreateStatic( const UBaseType_t uxQueueLength, const UBaseType_t uxItemSize, uint8_t *pucQueueStorage, StaticQueue_t *pxStaticQueue, const uint8_t ucQueueType ) PRIVILEGED_FUNCTION;
\r
1660 * Queue sets provide a mechanism to allow a task to block (pend) on a read
\r
1661 * operation from multiple queues or semaphores simultaneously.
\r
1663 * See FreeRTOS/Source/Demo/Common/Minimal/QueueSet.c for an example using this
\r
1666 * A queue set must be explicitly created using a call to xQueueCreateSet()
\r
1667 * before it can be used. Once created, standard FreeRTOS queues and semaphores
\r
1668 * can be added to the set using calls to xQueueAddToSet().
\r
1669 * xQueueSelectFromSet() is then used to determine which, if any, of the queues
\r
1670 * or semaphores contained in the set is in a state where a queue read or
\r
1671 * semaphore take operation would be successful.
\r
1673 * Note 1: See the documentation on http://wwwFreeRTOS.org/RTOS-queue-sets.html
\r
1674 * for reasons why queue sets are very rarely needed in practice as there are
\r
1675 * simpler methods of blocking on multiple objects.
\r
1677 * Note 2: Blocking on a queue set that contains a mutex will not cause the
\r
1678 * mutex holder to inherit the priority of the blocked task.
\r
1680 * Note 3: An additional 4 bytes of RAM is required for each space in a every
\r
1681 * queue added to a queue set. Therefore counting semaphores that have a high
\r
1682 * maximum count value should not be added to a queue set.
\r
1684 * Note 4: A receive (in the case of a queue) or take (in the case of a
\r
1685 * semaphore) operation must not be performed on a member of a queue set unless
\r
1686 * a call to xQueueSelectFromSet() has first returned a handle to that set member.
\r
1688 * @param uxEventQueueLength Queue sets store events that occur on
\r
1689 * the queues and semaphores contained in the set. uxEventQueueLength specifies
\r
1690 * the maximum number of events that can be queued at once. To be absolutely
\r
1691 * certain that events are not lost uxEventQueueLength should be set to the
\r
1692 * total sum of the length of the queues added to the set, where binary
\r
1693 * semaphores and mutexes have a length of 1, and counting semaphores have a
\r
1694 * length set by their maximum count value. Examples:
\r
1695 * + If a queue set is to hold a queue of length 5, another queue of length 12,
\r
1696 * and a binary semaphore, then uxEventQueueLength should be set to
\r
1697 * (5 + 12 + 1), or 18.
\r
1698 * + If a queue set is to hold three binary semaphores then uxEventQueueLength
\r
1699 * should be set to (1 + 1 + 1 ), or 3.
\r
1700 * + If a queue set is to hold a counting semaphore that has a maximum count of
\r
1701 * 5, and a counting semaphore that has a maximum count of 3, then
\r
1702 * uxEventQueueLength should be set to (5 + 3), or 8.
\r
1704 * @return If the queue set is created successfully then a handle to the created
\r
1705 * queue set is returned. Otherwise NULL is returned.
\r
1707 QueueSetHandle_t xQueueCreateSet( const UBaseType_t uxEventQueueLength ) PRIVILEGED_FUNCTION;
\r
1710 * Adds a queue or semaphore to a queue set that was previously created by a
\r
1711 * call to xQueueCreateSet().
\r
1713 * See FreeRTOS/Source/Demo/Common/Minimal/QueueSet.c for an example using this
\r
1716 * Note 1: A receive (in the case of a queue) or take (in the case of a
\r
1717 * semaphore) operation must not be performed on a member of a queue set unless
\r
1718 * a call to xQueueSelectFromSet() has first returned a handle to that set member.
\r
1720 * @param xQueueOrSemaphore The handle of the queue or semaphore being added to
\r
1721 * the queue set (cast to an QueueSetMemberHandle_t type).
\r
1723 * @param xQueueSet The handle of the queue set to which the queue or semaphore
\r
1726 * @return If the queue or semaphore was successfully added to the queue set
\r
1727 * then pdPASS is returned. If the queue could not be successfully added to the
\r
1728 * queue set because it is already a member of a different queue set then pdFAIL
\r
1731 BaseType_t xQueueAddToSet( QueueSetMemberHandle_t xQueueOrSemaphore, QueueSetHandle_t xQueueSet ) PRIVILEGED_FUNCTION;
\r
1734 * Removes a queue or semaphore from a queue set. A queue or semaphore can only
\r
1735 * be removed from a set if the queue or semaphore is empty.
\r
1737 * See FreeRTOS/Source/Demo/Common/Minimal/QueueSet.c for an example using this
\r
1740 * @param xQueueOrSemaphore The handle of the queue or semaphore being removed
\r
1741 * from the queue set (cast to an QueueSetMemberHandle_t type).
\r
1743 * @param xQueueSet The handle of the queue set in which the queue or semaphore
\r
1746 * @return If the queue or semaphore was successfully removed from the queue set
\r
1747 * then pdPASS is returned. If the queue was not in the queue set, or the
\r
1748 * queue (or semaphore) was not empty, then pdFAIL is returned.
\r
1750 BaseType_t xQueueRemoveFromSet( QueueSetMemberHandle_t xQueueOrSemaphore, QueueSetHandle_t xQueueSet ) PRIVILEGED_FUNCTION;
\r
1753 * xQueueSelectFromSet() selects from the members of a queue set a queue or
\r
1754 * semaphore that either contains data (in the case of a queue) or is available
\r
1755 * to take (in the case of a semaphore). xQueueSelectFromSet() effectively
\r
1756 * allows a task to block (pend) on a read operation on all the queues and
\r
1757 * semaphores in a queue set simultaneously.
\r
1759 * See FreeRTOS/Source/Demo/Common/Minimal/QueueSet.c for an example using this
\r
1762 * Note 1: See the documentation on http://wwwFreeRTOS.org/RTOS-queue-sets.html
\r
1763 * for reasons why queue sets are very rarely needed in practice as there are
\r
1764 * simpler methods of blocking on multiple objects.
\r
1766 * Note 2: Blocking on a queue set that contains a mutex will not cause the
\r
1767 * mutex holder to inherit the priority of the blocked task.
\r
1769 * Note 3: A receive (in the case of a queue) or take (in the case of a
\r
1770 * semaphore) operation must not be performed on a member of a queue set unless
\r
1771 * a call to xQueueSelectFromSet() has first returned a handle to that set member.
\r
1773 * @param xQueueSet The queue set on which the task will (potentially) block.
\r
1775 * @param xTicksToWait The maximum time, in ticks, that the calling task will
\r
1776 * remain in the Blocked state (with other tasks executing) to wait for a member
\r
1777 * of the queue set to be ready for a successful queue read or semaphore take
\r
1780 * @return xQueueSelectFromSet() will return the handle of a queue (cast to
\r
1781 * a QueueSetMemberHandle_t type) contained in the queue set that contains data,
\r
1782 * or the handle of a semaphore (cast to a QueueSetMemberHandle_t type) contained
\r
1783 * in the queue set that is available, or NULL if no such queue or semaphore
\r
1784 * exists before before the specified block time expires.
\r
1786 QueueSetMemberHandle_t xQueueSelectFromSet( QueueSetHandle_t xQueueSet, const TickType_t xTicksToWait ) PRIVILEGED_FUNCTION;
\r
1789 * A version of xQueueSelectFromSet() that can be used from an ISR.
\r
1791 QueueSetMemberHandle_t xQueueSelectFromSetFromISR( QueueSetHandle_t xQueueSet ) PRIVILEGED_FUNCTION;
\r
1793 /* Not public API functions. */
\r
1794 void vQueueWaitForMessageRestricted( QueueHandle_t xQueue, TickType_t xTicksToWait, const BaseType_t xWaitIndefinitely ) PRIVILEGED_FUNCTION;
\r
1795 BaseType_t xQueueGenericReset( QueueHandle_t xQueue, BaseType_t xNewQueue ) PRIVILEGED_FUNCTION;
\r
1796 void vQueueSetQueueNumber( QueueHandle_t xQueue, UBaseType_t uxQueueNumber ) PRIVILEGED_FUNCTION;
\r
1797 UBaseType_t uxQueueGetQueueNumber( QueueHandle_t xQueue ) PRIVILEGED_FUNCTION;
\r
1798 uint8_t ucQueueGetQueueType( QueueHandle_t xQueue ) PRIVILEGED_FUNCTION;
\r
1801 #ifdef __cplusplus
\r
1805 #endif /* QUEUE_H */
\r