2 FreeRTOS V7.5.1 - Copyright (C) 2013 Real Time Engineers Ltd.
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4 VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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6 ***************************************************************************
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8 * FreeRTOS provides completely free yet professionally developed, *
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9 * robust, strictly quality controlled, supported, and cross *
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10 * platform software that has become a de facto standard. *
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12 * Help yourself get started quickly and support the FreeRTOS *
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13 * project by purchasing a FreeRTOS tutorial book, reference *
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14 * manual, or both from: http://www.FreeRTOS.org/Documentation *
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18 ***************************************************************************
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20 This file is part of the FreeRTOS distribution.
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22 FreeRTOS is free software; you can redistribute it and/or modify it under
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23 the terms of the GNU General Public License (version 2) as published by the
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24 Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.
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26 >>! NOTE: The modification to the GPL is included to allow you to distribute
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27 >>! a combined work that includes FreeRTOS without being obliged to provide
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28 >>! the source code for proprietary components outside of the FreeRTOS
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31 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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32 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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33 FOR A PARTICULAR PURPOSE. Full license text is available from the following
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34 link: http://www.freertos.org/a00114.html
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38 ***************************************************************************
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40 * Having a problem? Start by reading the FAQ "My application does *
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41 * not run, what could be wrong?" *
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43 * http://www.FreeRTOS.org/FAQHelp.html *
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45 ***************************************************************************
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47 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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48 license and Real Time Engineers Ltd. contact details.
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50 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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51 including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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52 compatible FAT file system, and our tiny thread aware UDP/IP stack.
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54 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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55 Integrity Systems to sell under the OpenRTOS brand. Low cost OpenRTOS
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56 licenses offer ticketed support, indemnification and middleware.
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58 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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59 engineered and independently SIL3 certified version for use in safety and
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60 mission critical applications that require provable dependability.
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69 #ifndef INC_FREERTOS_H
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70 #error "include FreeRTOS.h" must appear in source files before "include queue.h"
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79 * Type by which queues are referenced. For example, a call to xQueueCreate()
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80 * returns an xQueueHandle variable that can then be used as a parameter to
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81 * xQueueSend(), xQueueReceive(), etc.
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83 typedef void * xQueueHandle;
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86 * Type by which queue sets are referenced. For example, a call to
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87 * xQueueCreateSet() returns an xQueueSet variable that can then be used as a
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88 * parameter to xQueueSelectFromSet(), xQueueAddToSet(), etc.
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90 typedef void * xQueueSetHandle;
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93 * Queue sets can contain both queues and semaphores, so the
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94 * xQueueSetMemberHandle is defined as a type to be used where a parameter or
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95 * return value can be either an xQueueHandle or an xSemaphoreHandle.
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97 typedef void * xQueueSetMemberHandle;
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99 /* For internal use only. */
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100 #define queueSEND_TO_BACK ( ( portBASE_TYPE ) 0 )
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101 #define queueSEND_TO_FRONT ( ( portBASE_TYPE ) 1 )
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102 #define queueOVERWRITE ( ( portBASE_TYPE ) 2 )
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104 /* For internal use only. These definitions *must* match those in queue.c. */
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105 #define queueQUEUE_TYPE_BASE ( ( unsigned char ) 0U )
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106 #define queueQUEUE_TYPE_SET ( ( unsigned char ) 0U )
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107 #define queueQUEUE_TYPE_MUTEX ( ( unsigned char ) 1U )
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108 #define queueQUEUE_TYPE_COUNTING_SEMAPHORE ( ( unsigned char ) 2U )
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109 #define queueQUEUE_TYPE_BINARY_SEMAPHORE ( ( unsigned char ) 3U )
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110 #define queueQUEUE_TYPE_RECURSIVE_MUTEX ( ( unsigned char ) 4U )
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115 xQueueHandle xQueueCreate(
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116 unsigned portBASE_TYPE uxQueueLength,
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117 unsigned portBASE_TYPE uxItemSize
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121 * Creates a new queue instance. This allocates the storage required by the
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122 * new queue and returns a handle for the queue.
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124 * @param uxQueueLength The maximum number of items that the queue can contain.
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126 * @param uxItemSize The number of bytes each item in the queue will require.
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127 * Items are queued by copy, not by reference, so this is the number of bytes
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128 * that will be copied for each posted item. Each item on the queue must be
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131 * @return If the queue is successfully create then a handle to the newly
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132 * created queue is returned. If the queue cannot be created then 0 is
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143 void vATask( void *pvParameters )
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145 xQueueHandle xQueue1, xQueue2;
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147 // Create a queue capable of containing 10 unsigned long values.
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148 xQueue1 = xQueueCreate( 10, sizeof( unsigned long ) );
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151 // Queue was not created and must not be used.
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154 // Create a queue capable of containing 10 pointers to AMessage structures.
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155 // These should be passed by pointer as they contain a lot of data.
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156 xQueue2 = xQueueCreate( 10, sizeof( struct AMessage * ) );
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159 // Queue was not created and must not be used.
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162 // ... Rest of task code.
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165 * \defgroup xQueueCreate xQueueCreate
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166 * \ingroup QueueManagement
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168 #define xQueueCreate( uxQueueLength, uxItemSize ) xQueueGenericCreate( uxQueueLength, uxItemSize, queueQUEUE_TYPE_BASE )
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173 portBASE_TYPE xQueueSendToToFront(
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174 xQueueHandle xQueue,
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175 const void * pvItemToQueue,
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176 portTickType xTicksToWait
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180 * This is a macro that calls xQueueGenericSend().
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182 * Post an item to the front of a queue. The item is queued by copy, not by
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183 * reference. This function must not be called from an interrupt service
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184 * routine. See xQueueSendFromISR () for an alternative which may be used
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187 * @param xQueue The handle to the queue on which the item is to be posted.
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189 * @param pvItemToQueue A pointer to the item that is to be placed on the
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190 * queue. The size of the items the queue will hold was defined when the
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191 * queue was created, so this many bytes will be copied from pvItemToQueue
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192 * into the queue storage area.
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194 * @param xTicksToWait The maximum amount of time the task should block
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195 * waiting for space to become available on the queue, should it already
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196 * be full. The call will return immediately if this is set to 0 and the
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197 * queue is full. The time is defined in tick periods so the constant
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198 * portTICK_RATE_MS should be used to convert to real time if this is required.
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200 * @return pdTRUE if the item was successfully posted, otherwise errQUEUE_FULL.
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210 unsigned long ulVar = 10UL;
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212 void vATask( void *pvParameters )
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214 xQueueHandle xQueue1, xQueue2;
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215 struct AMessage *pxMessage;
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217 // Create a queue capable of containing 10 unsigned long values.
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218 xQueue1 = xQueueCreate( 10, sizeof( unsigned long ) );
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220 // Create a queue capable of containing 10 pointers to AMessage structures.
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221 // These should be passed by pointer as they contain a lot of data.
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222 xQueue2 = xQueueCreate( 10, sizeof( struct AMessage * ) );
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228 // Send an unsigned long. Wait for 10 ticks for space to become
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229 // available if necessary.
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230 if( xQueueSendToFront( xQueue1, ( void * ) &ulVar, ( portTickType ) 10 ) != pdPASS )
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232 // Failed to post the message, even after 10 ticks.
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238 // Send a pointer to a struct AMessage object. Don't block if the
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239 // queue is already full.
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240 pxMessage = & xMessage;
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241 xQueueSendToFront( xQueue2, ( void * ) &pxMessage, ( portTickType ) 0 );
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244 // ... Rest of task code.
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247 * \defgroup xQueueSend xQueueSend
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248 * \ingroup QueueManagement
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250 #define xQueueSendToFront( xQueue, pvItemToQueue, xTicksToWait ) xQueueGenericSend( ( xQueue ), ( pvItemToQueue ), ( xTicksToWait ), queueSEND_TO_FRONT )
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255 portBASE_TYPE xQueueSendToBack(
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256 xQueueHandle xQueue,
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257 const void * pvItemToQueue,
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258 portTickType xTicksToWait
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262 * This is a macro that calls xQueueGenericSend().
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264 * Post an item to the back of a queue. The item is queued by copy, not by
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265 * reference. This function must not be called from an interrupt service
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266 * routine. See xQueueSendFromISR () for an alternative which may be used
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269 * @param xQueue The handle to the queue on which the item is to be posted.
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271 * @param pvItemToQueue A pointer to the item that is to be placed on the
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272 * queue. The size of the items the queue will hold was defined when the
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273 * queue was created, so this many bytes will be copied from pvItemToQueue
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274 * into the queue storage area.
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276 * @param xTicksToWait The maximum amount of time the task should block
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277 * waiting for space to become available on the queue, should it already
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278 * be full. The call will return immediately if this is set to 0 and the queue
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279 * is full. The time is defined in tick periods so the constant
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280 * portTICK_RATE_MS should be used to convert to real time if this is required.
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282 * @return pdTRUE if the item was successfully posted, otherwise errQUEUE_FULL.
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292 unsigned long ulVar = 10UL;
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294 void vATask( void *pvParameters )
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296 xQueueHandle xQueue1, xQueue2;
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297 struct AMessage *pxMessage;
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299 // Create a queue capable of containing 10 unsigned long values.
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300 xQueue1 = xQueueCreate( 10, sizeof( unsigned long ) );
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302 // Create a queue capable of containing 10 pointers to AMessage structures.
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303 // These should be passed by pointer as they contain a lot of data.
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304 xQueue2 = xQueueCreate( 10, sizeof( struct AMessage * ) );
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310 // Send an unsigned long. Wait for 10 ticks for space to become
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311 // available if necessary.
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312 if( xQueueSendToBack( xQueue1, ( void * ) &ulVar, ( portTickType ) 10 ) != pdPASS )
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314 // Failed to post the message, even after 10 ticks.
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320 // Send a pointer to a struct AMessage object. Don't block if the
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321 // queue is already full.
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322 pxMessage = & xMessage;
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323 xQueueSendToBack( xQueue2, ( void * ) &pxMessage, ( portTickType ) 0 );
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326 // ... Rest of task code.
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329 * \defgroup xQueueSend xQueueSend
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330 * \ingroup QueueManagement
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332 #define xQueueSendToBack( xQueue, pvItemToQueue, xTicksToWait ) xQueueGenericSend( ( xQueue ), ( pvItemToQueue ), ( xTicksToWait ), queueSEND_TO_BACK )
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337 portBASE_TYPE xQueueSend(
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338 xQueueHandle xQueue,
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339 const void * pvItemToQueue,
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340 portTickType xTicksToWait
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344 * This is a macro that calls xQueueGenericSend(). It is included for
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345 * backward compatibility with versions of FreeRTOS.org that did not
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346 * include the xQueueSendToFront() and xQueueSendToBack() macros. It is
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347 * equivalent to xQueueSendToBack().
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349 * Post an item on a queue. The item is queued by copy, not by reference.
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350 * This function must not be called from an interrupt service routine.
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351 * See xQueueSendFromISR () for an alternative which may be used in an ISR.
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353 * @param xQueue The handle to the queue on which the item is to be posted.
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355 * @param pvItemToQueue A pointer to the item that is to be placed on the
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356 * queue. The size of the items the queue will hold was defined when the
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357 * queue was created, so this many bytes will be copied from pvItemToQueue
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358 * into the queue storage area.
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360 * @param xTicksToWait The maximum amount of time the task should block
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361 * waiting for space to become available on the queue, should it already
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362 * be full. The call will return immediately if this is set to 0 and the
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363 * queue is full. The time is defined in tick periods so the constant
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364 * portTICK_RATE_MS should be used to convert to real time if this is required.
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366 * @return pdTRUE if the item was successfully posted, otherwise errQUEUE_FULL.
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376 unsigned long ulVar = 10UL;
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378 void vATask( void *pvParameters )
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380 xQueueHandle xQueue1, xQueue2;
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381 struct AMessage *pxMessage;
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383 // Create a queue capable of containing 10 unsigned long values.
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384 xQueue1 = xQueueCreate( 10, sizeof( unsigned long ) );
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386 // Create a queue capable of containing 10 pointers to AMessage structures.
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387 // These should be passed by pointer as they contain a lot of data.
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388 xQueue2 = xQueueCreate( 10, sizeof( struct AMessage * ) );
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394 // Send an unsigned long. Wait for 10 ticks for space to become
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395 // available if necessary.
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396 if( xQueueSend( xQueue1, ( void * ) &ulVar, ( portTickType ) 10 ) != pdPASS )
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398 // Failed to post the message, even after 10 ticks.
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404 // Send a pointer to a struct AMessage object. Don't block if the
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405 // queue is already full.
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406 pxMessage = & xMessage;
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407 xQueueSend( xQueue2, ( void * ) &pxMessage, ( portTickType ) 0 );
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410 // ... Rest of task code.
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413 * \defgroup xQueueSend xQueueSend
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414 * \ingroup QueueManagement
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416 #define xQueueSend( xQueue, pvItemToQueue, xTicksToWait ) xQueueGenericSend( ( xQueue ), ( pvItemToQueue ), ( xTicksToWait ), queueSEND_TO_BACK )
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421 portBASE_TYPE xQueueOverwrite(
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422 xQueueHandle xQueue,
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423 const void * pvItemToQueue
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427 * Only for use with queues that have a length of one - so the queue is either
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430 * Post an item on a queue. If the queue is already full then overwrite the
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431 * value held in the queue. The item is queued by copy, not by reference.
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433 * This function must not be called from an interrupt service routine.
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434 * See xQueueOverwriteFromISR () for an alternative which may be used in an ISR.
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436 * @param xQueue The handle of the queue to which the data is being sent.
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438 * @param pvItemToQueue A pointer to the item that is to be placed on the
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439 * queue. The size of the items the queue will hold was defined when the
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440 * queue was created, so this many bytes will be copied from pvItemToQueue
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441 * into the queue storage area.
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443 * @return xQueueOverwrite() is a macro that calls xQueueGenericSend(), and
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444 * therefore has the same return values as xQueueSendToFront(). However, pdPASS
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445 * is the only value that can be returned because xQueueOverwrite() will write
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446 * to the queue even when the queue is already full.
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451 void vFunction( void *pvParameters )
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453 xQueueHandle xQueue;
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454 unsigned long ulVarToSend, ulValReceived;
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456 // Create a queue to hold one unsigned long value. It is strongly
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457 // recommended *not* to use xQueueOverwrite() on queues that can
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458 // contain more than one value, and doing so will trigger an assertion
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459 // if configASSERT() is defined.
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460 xQueue = xQueueCreate( 1, sizeof( unsigned long ) );
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462 // Write the value 10 to the queue using xQueueOverwrite().
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464 xQueueOverwrite( xQueue, &ulVarToSend );
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466 // Peeking the queue should now return 10, but leave the value 10 in
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467 // the queue. A block time of zero is used as it is known that the
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468 // queue holds a value.
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470 xQueuePeek( xQueue, &ulValReceived, 0 );
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472 if( ulValReceived != 10 )
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474 // Error unless the item was removed by a different task.
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477 // The queue is still full. Use xQueueOverwrite() to overwrite the
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478 // value held in the queue with 100.
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480 xQueueOverwrite( xQueue, &ulVarToSend );
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482 // This time read from the queue, leaving the queue empty once more.
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483 // A block time of 0 is used again.
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484 xQueueReceive( xQueue, &ulValReceived, 0 );
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486 // The value read should be the last value written, even though the
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487 // queue was already full when the value was written.
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488 if( ulValReceived != 100 )
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496 * \defgroup xQueueOverwrite xQueueOverwrite
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497 * \ingroup QueueManagement
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499 #define xQueueOverwrite( xQueue, pvItemToQueue ) xQueueGenericSend( ( xQueue ), ( pvItemToQueue ), 0, queueOVERWRITE )
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505 portBASE_TYPE xQueueGenericSend(
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506 xQueueHandle xQueue,
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507 const void * pvItemToQueue,
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508 portTickType xTicksToWait
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509 portBASE_TYPE xCopyPosition
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513 * It is preferred that the macros xQueueSend(), xQueueSendToFront() and
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514 * xQueueSendToBack() are used in place of calling this function directly.
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516 * Post an item on a queue. The item is queued by copy, not by reference.
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517 * This function must not be called from an interrupt service routine.
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518 * See xQueueSendFromISR () for an alternative which may be used in an ISR.
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520 * @param xQueue The handle to the queue on which the item is to be posted.
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522 * @param pvItemToQueue A pointer to the item that is to be placed on the
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523 * queue. The size of the items the queue will hold was defined when the
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524 * queue was created, so this many bytes will be copied from pvItemToQueue
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525 * into the queue storage area.
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527 * @param xTicksToWait The maximum amount of time the task should block
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528 * waiting for space to become available on the queue, should it already
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529 * be full. The call will return immediately if this is set to 0 and the
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530 * queue is full. The time is defined in tick periods so the constant
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531 * portTICK_RATE_MS should be used to convert to real time if this is required.
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533 * @param xCopyPosition Can take the value queueSEND_TO_BACK to place the
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534 * item at the back of the queue, or queueSEND_TO_FRONT to place the item
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535 * at the front of the queue (for high priority messages).
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537 * @return pdTRUE if the item was successfully posted, otherwise errQUEUE_FULL.
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547 unsigned long ulVar = 10UL;
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549 void vATask( void *pvParameters )
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551 xQueueHandle xQueue1, xQueue2;
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552 struct AMessage *pxMessage;
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554 // Create a queue capable of containing 10 unsigned long values.
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555 xQueue1 = xQueueCreate( 10, sizeof( unsigned long ) );
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557 // Create a queue capable of containing 10 pointers to AMessage structures.
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558 // These should be passed by pointer as they contain a lot of data.
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559 xQueue2 = xQueueCreate( 10, sizeof( struct AMessage * ) );
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565 // Send an unsigned long. Wait for 10 ticks for space to become
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566 // available if necessary.
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567 if( xQueueGenericSend( xQueue1, ( void * ) &ulVar, ( portTickType ) 10, queueSEND_TO_BACK ) != pdPASS )
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569 // Failed to post the message, even after 10 ticks.
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575 // Send a pointer to a struct AMessage object. Don't block if the
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576 // queue is already full.
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577 pxMessage = & xMessage;
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578 xQueueGenericSend( xQueue2, ( void * ) &pxMessage, ( portTickType ) 0, queueSEND_TO_BACK );
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581 // ... Rest of task code.
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584 * \defgroup xQueueSend xQueueSend
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585 * \ingroup QueueManagement
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587 signed portBASE_TYPE xQueueGenericSend( xQueueHandle xQueue, const void * const pvItemToQueue, portTickType xTicksToWait, portBASE_TYPE xCopyPosition ) PRIVILEGED_FUNCTION;
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592 portBASE_TYPE xQueuePeek(
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593 xQueueHandle xQueue,
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595 portTickType xTicksToWait
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598 * This is a macro that calls the xQueueGenericReceive() function.
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600 * Receive an item from a queue without removing the item from the queue.
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601 * The item is received by copy so a buffer of adequate size must be
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602 * provided. The number of bytes copied into the buffer was defined when
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603 * the queue was created.
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605 * Successfully received items remain on the queue so will be returned again
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606 * by the next call, or a call to xQueueReceive().
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608 * This macro must not be used in an interrupt service routine. See
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609 * xQueuePeekFromISR() for an alternative that can be called from an interrupt
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612 * @param xQueue The handle to the queue from which the item is to be
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615 * @param pvBuffer Pointer to the buffer into which the received item will
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618 * @param xTicksToWait The maximum amount of time the task should block
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619 * waiting for an item to receive should the queue be empty at the time
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620 * of the call. The time is defined in tick periods so the constant
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621 * portTICK_RATE_MS should be used to convert to real time if this is required.
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622 * xQueuePeek() will return immediately if xTicksToWait is 0 and the queue
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625 * @return pdTRUE if an item was successfully received from the queue,
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626 * otherwise pdFALSE.
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636 xQueueHandle xQueue;
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638 // Task to create a queue and post a value.
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639 void vATask( void *pvParameters )
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641 struct AMessage *pxMessage;
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643 // Create a queue capable of containing 10 pointers to AMessage structures.
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644 // These should be passed by pointer as they contain a lot of data.
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645 xQueue = xQueueCreate( 10, sizeof( struct AMessage * ) );
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648 // Failed to create the queue.
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653 // Send a pointer to a struct AMessage object. Don't block if the
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654 // queue is already full.
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655 pxMessage = & xMessage;
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656 xQueueSend( xQueue, ( void * ) &pxMessage, ( portTickType ) 0 );
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658 // ... Rest of task code.
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661 // Task to peek the data from the queue.
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662 void vADifferentTask( void *pvParameters )
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664 struct AMessage *pxRxedMessage;
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668 // Peek a message on the created queue. Block for 10 ticks if a
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669 // message is not immediately available.
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670 if( xQueuePeek( xQueue, &( pxRxedMessage ), ( portTickType ) 10 ) )
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672 // pcRxedMessage now points to the struct AMessage variable posted
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673 // by vATask, but the item still remains on the queue.
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677 // ... Rest of task code.
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680 * \defgroup xQueueReceive xQueueReceive
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681 * \ingroup QueueManagement
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683 #define xQueuePeek( xQueue, pvBuffer, xTicksToWait ) xQueueGenericReceive( ( xQueue ), ( pvBuffer ), ( xTicksToWait ), pdTRUE )
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688 portBASE_TYPE xQueuePeekFromISR(
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689 xQueueHandle xQueue,
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693 * A version of xQueuePeek() that can be called from an interrupt service
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696 * Receive an item from a queue without removing the item from the queue.
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697 * The item is received by copy so a buffer of adequate size must be
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698 * provided. The number of bytes copied into the buffer was defined when
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699 * the queue was created.
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701 * Successfully received items remain on the queue so will be returned again
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702 * by the next call, or a call to xQueueReceive().
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704 * @param xQueue The handle to the queue from which the item is to be
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707 * @param pvBuffer Pointer to the buffer into which the received item will
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710 * @return pdTRUE if an item was successfully received from the queue,
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711 * otherwise pdFALSE.
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713 * \defgroup xQueuePeekFromISR xQueuePeekFromISR
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714 * \ingroup QueueManagement
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716 signed portBASE_TYPE xQueuePeekFromISR( xQueueHandle xQueue, const void * const pvBuffer ) PRIVILEGED_FUNCTION;
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721 portBASE_TYPE xQueueReceive(
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722 xQueueHandle xQueue,
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724 portTickType xTicksToWait
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727 * This is a macro that calls the xQueueGenericReceive() function.
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729 * Receive an item from a queue. The item is received by copy so a buffer of
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730 * adequate size must be provided. The number of bytes copied into the buffer
\r
731 * was defined when the queue was created.
\r
733 * Successfully received items are removed from the queue.
\r
735 * This function must not be used in an interrupt service routine. See
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736 * xQueueReceiveFromISR for an alternative that can.
\r
738 * @param xQueue The handle to the queue from which the item is to be
\r
741 * @param pvBuffer Pointer to the buffer into which the received item will
\r
744 * @param xTicksToWait The maximum amount of time the task should block
\r
745 * waiting for an item to receive should the queue be empty at the time
\r
746 * of the call. xQueueReceive() will return immediately if xTicksToWait
\r
747 * is zero and the queue is empty. The time is defined in tick periods so the
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748 * constant portTICK_RATE_MS should be used to convert to real time if this is
\r
751 * @return pdTRUE if an item was successfully received from the queue,
\r
752 * otherwise pdFALSE.
\r
762 xQueueHandle xQueue;
\r
764 // Task to create a queue and post a value.
\r
765 void vATask( void *pvParameters )
\r
767 struct AMessage *pxMessage;
\r
769 // Create a queue capable of containing 10 pointers to AMessage structures.
\r
770 // These should be passed by pointer as they contain a lot of data.
\r
771 xQueue = xQueueCreate( 10, sizeof( struct AMessage * ) );
\r
774 // Failed to create the queue.
\r
779 // Send a pointer to a struct AMessage object. Don't block if the
\r
780 // queue is already full.
\r
781 pxMessage = & xMessage;
\r
782 xQueueSend( xQueue, ( void * ) &pxMessage, ( portTickType ) 0 );
\r
784 // ... Rest of task code.
\r
787 // Task to receive from the queue.
\r
788 void vADifferentTask( void *pvParameters )
\r
790 struct AMessage *pxRxedMessage;
\r
794 // Receive a message on the created queue. Block for 10 ticks if a
\r
795 // message is not immediately available.
\r
796 if( xQueueReceive( xQueue, &( pxRxedMessage ), ( portTickType ) 10 ) )
\r
798 // pcRxedMessage now points to the struct AMessage variable posted
\r
803 // ... Rest of task code.
\r
806 * \defgroup xQueueReceive xQueueReceive
\r
807 * \ingroup QueueManagement
\r
809 #define xQueueReceive( xQueue, pvBuffer, xTicksToWait ) xQueueGenericReceive( ( xQueue ), ( pvBuffer ), ( xTicksToWait ), pdFALSE )
\r
815 portBASE_TYPE xQueueGenericReceive(
\r
816 xQueueHandle xQueue,
\r
818 portTickType xTicksToWait
\r
819 portBASE_TYPE xJustPeek
\r
822 * It is preferred that the macro xQueueReceive() be used rather than calling
\r
823 * this function directly.
\r
825 * Receive an item from a queue. The item is received by copy so a buffer of
\r
826 * adequate size must be provided. The number of bytes copied into the buffer
\r
827 * was defined when the queue was created.
\r
829 * This function must not be used in an interrupt service routine. See
\r
830 * xQueueReceiveFromISR for an alternative that can.
\r
832 * @param xQueue The handle to the queue from which the item is to be
\r
835 * @param pvBuffer Pointer to the buffer into which the received item will
\r
838 * @param xTicksToWait The maximum amount of time the task should block
\r
839 * waiting for an item to receive should the queue be empty at the time
\r
840 * of the call. The time is defined in tick periods so the constant
\r
841 * portTICK_RATE_MS should be used to convert to real time if this is required.
\r
842 * xQueueGenericReceive() will return immediately if the queue is empty and
\r
843 * xTicksToWait is 0.
\r
845 * @param xJustPeek When set to true, the item received from the queue is not
\r
846 * actually removed from the queue - meaning a subsequent call to
\r
847 * xQueueReceive() will return the same item. When set to false, the item
\r
848 * being received from the queue is also removed from the queue.
\r
850 * @return pdTRUE if an item was successfully received from the queue,
\r
851 * otherwise pdFALSE.
\r
861 xQueueHandle xQueue;
\r
863 // Task to create a queue and post a value.
\r
864 void vATask( void *pvParameters )
\r
866 struct AMessage *pxMessage;
\r
868 // Create a queue capable of containing 10 pointers to AMessage structures.
\r
869 // These should be passed by pointer as they contain a lot of data.
\r
870 xQueue = xQueueCreate( 10, sizeof( struct AMessage * ) );
\r
873 // Failed to create the queue.
\r
878 // Send a pointer to a struct AMessage object. Don't block if the
\r
879 // queue is already full.
\r
880 pxMessage = & xMessage;
\r
881 xQueueSend( xQueue, ( void * ) &pxMessage, ( portTickType ) 0 );
\r
883 // ... Rest of task code.
\r
886 // Task to receive from the queue.
\r
887 void vADifferentTask( void *pvParameters )
\r
889 struct AMessage *pxRxedMessage;
\r
893 // Receive a message on the created queue. Block for 10 ticks if a
\r
894 // message is not immediately available.
\r
895 if( xQueueGenericReceive( xQueue, &( pxRxedMessage ), ( portTickType ) 10 ) )
\r
897 // pcRxedMessage now points to the struct AMessage variable posted
\r
902 // ... Rest of task code.
\r
905 * \defgroup xQueueReceive xQueueReceive
\r
906 * \ingroup QueueManagement
\r
908 signed portBASE_TYPE xQueueGenericReceive( xQueueHandle xQueue, const void * const pvBuffer, portTickType xTicksToWait, portBASE_TYPE xJustPeek ) PRIVILEGED_FUNCTION;
\r
912 * <pre>unsigned portBASE_TYPE uxQueueMessagesWaiting( const xQueueHandle xQueue );</pre>
\r
914 * Return the number of messages stored in a queue.
\r
916 * @param xQueue A handle to the queue being queried.
\r
918 * @return The number of messages available in the queue.
\r
920 * \defgroup uxQueueMessagesWaiting uxQueueMessagesWaiting
\r
921 * \ingroup QueueManagement
\r
923 unsigned portBASE_TYPE uxQueueMessagesWaiting( const xQueueHandle xQueue ) PRIVILEGED_FUNCTION;
\r
927 * <pre>void vQueueDelete( xQueueHandle xQueue );</pre>
\r
929 * Delete a queue - freeing all the memory allocated for storing of items
\r
930 * placed on the queue.
\r
932 * @param xQueue A handle to the queue to be deleted.
\r
934 * \defgroup vQueueDelete vQueueDelete
\r
935 * \ingroup QueueManagement
\r
937 void vQueueDelete( xQueueHandle xQueue ) PRIVILEGED_FUNCTION;
\r
942 portBASE_TYPE xQueueSendToFrontFromISR(
\r
943 xQueueHandle xQueue,
\r
944 const void *pvItemToQueue,
\r
945 portBASE_TYPE *pxHigherPriorityTaskWoken
\r
949 * This is a macro that calls xQueueGenericSendFromISR().
\r
951 * Post an item to the front of a queue. It is safe to use this macro from
\r
952 * within an interrupt service routine.
\r
954 * Items are queued by copy not reference so it is preferable to only
\r
955 * queue small items, especially when called from an ISR. In most cases
\r
956 * it would be preferable to store a pointer to the item being queued.
\r
958 * @param xQueue The handle to the queue on which the item is to be posted.
\r
960 * @param pvItemToQueue A pointer to the item that is to be placed on the
\r
961 * queue. The size of the items the queue will hold was defined when the
\r
962 * queue was created, so this many bytes will be copied from pvItemToQueue
\r
963 * into the queue storage area.
\r
965 * @param pxHigherPriorityTaskWoken xQueueSendToFrontFromISR() will set
\r
966 * *pxHigherPriorityTaskWoken to pdTRUE if sending to the queue caused a task
\r
967 * to unblock, and the unblocked task has a priority higher than the currently
\r
968 * running task. If xQueueSendToFromFromISR() sets this value to pdTRUE then
\r
969 * a context switch should be requested before the interrupt is exited.
\r
971 * @return pdTRUE if the data was successfully sent to the queue, otherwise
\r
974 * Example usage for buffered IO (where the ISR can obtain more than one value
\r
977 void vBufferISR( void )
\r
980 portBASE_TYPE xHigherPrioritTaskWoken;
\r
982 // We have not woken a task at the start of the ISR.
\r
983 xHigherPriorityTaskWoken = pdFALSE;
\r
985 // Loop until the buffer is empty.
\r
988 // Obtain a byte from the buffer.
\r
989 cIn = portINPUT_BYTE( RX_REGISTER_ADDRESS );
\r
992 xQueueSendToFrontFromISR( xRxQueue, &cIn, &xHigherPriorityTaskWoken );
\r
994 } while( portINPUT_BYTE( BUFFER_COUNT ) );
\r
996 // Now the buffer is empty we can switch context if necessary.
\r
997 if( xHigherPriorityTaskWoken )
\r
1004 * \defgroup xQueueSendFromISR xQueueSendFromISR
\r
1005 * \ingroup QueueManagement
\r
1007 #define xQueueSendToFrontFromISR( xQueue, pvItemToQueue, pxHigherPriorityTaskWoken ) xQueueGenericSendFromISR( ( xQueue ), ( pvItemToQueue ), ( pxHigherPriorityTaskWoken ), queueSEND_TO_FRONT )
\r
1013 portBASE_TYPE xQueueSendToBackFromISR(
\r
1014 xQueueHandle xQueue,
\r
1015 const void *pvItemToQueue,
\r
1016 portBASE_TYPE *pxHigherPriorityTaskWoken
\r
1020 * This is a macro that calls xQueueGenericSendFromISR().
\r
1022 * Post an item to the back of a queue. It is safe to use this macro from
\r
1023 * within an interrupt service routine.
\r
1025 * Items are queued by copy not reference so it is preferable to only
\r
1026 * queue small items, especially when called from an ISR. In most cases
\r
1027 * it would be preferable to store a pointer to the item being queued.
\r
1029 * @param xQueue The handle to the queue on which the item is to be posted.
\r
1031 * @param pvItemToQueue A pointer to the item that is to be placed on the
\r
1032 * queue. The size of the items the queue will hold was defined when the
\r
1033 * queue was created, so this many bytes will be copied from pvItemToQueue
\r
1034 * into the queue storage area.
\r
1036 * @param pxHigherPriorityTaskWoken xQueueSendToBackFromISR() will set
\r
1037 * *pxHigherPriorityTaskWoken to pdTRUE if sending to the queue caused a task
\r
1038 * to unblock, and the unblocked task has a priority higher than the currently
\r
1039 * running task. If xQueueSendToBackFromISR() sets this value to pdTRUE then
\r
1040 * a context switch should be requested before the interrupt is exited.
\r
1042 * @return pdTRUE if the data was successfully sent to the queue, otherwise
\r
1045 * Example usage for buffered IO (where the ISR can obtain more than one value
\r
1048 void vBufferISR( void )
\r
1051 portBASE_TYPE xHigherPriorityTaskWoken;
\r
1053 // We have not woken a task at the start of the ISR.
\r
1054 xHigherPriorityTaskWoken = pdFALSE;
\r
1056 // Loop until the buffer is empty.
\r
1059 // Obtain a byte from the buffer.
\r
1060 cIn = portINPUT_BYTE( RX_REGISTER_ADDRESS );
\r
1063 xQueueSendToBackFromISR( xRxQueue, &cIn, &xHigherPriorityTaskWoken );
\r
1065 } while( portINPUT_BYTE( BUFFER_COUNT ) );
\r
1067 // Now the buffer is empty we can switch context if necessary.
\r
1068 if( xHigherPriorityTaskWoken )
\r
1075 * \defgroup xQueueSendFromISR xQueueSendFromISR
\r
1076 * \ingroup QueueManagement
\r
1078 #define xQueueSendToBackFromISR( xQueue, pvItemToQueue, pxHigherPriorityTaskWoken ) xQueueGenericSendFromISR( ( xQueue ), ( pvItemToQueue ), ( pxHigherPriorityTaskWoken ), queueSEND_TO_BACK )
\r
1083 portBASE_TYPE xQueueOverwriteFromISR(
\r
1084 xQueueHandle xQueue,
\r
1085 const void * pvItemToQueue,
\r
1086 portBASE_TYPE *pxHigherPriorityTaskWoken
\r
1090 * A version of xQueueOverwrite() that can be used in an interrupt service
\r
1093 * Only for use with queues that can hold a single item - so the queue is either
\r
1096 * Post an item on a queue. If the queue is already full then overwrite the
\r
1097 * value held in the queue. The item is queued by copy, not by reference.
\r
1099 * @param xQueue The handle to the queue on which the item is to be posted.
\r
1101 * @param pvItemToQueue A pointer to the item that is to be placed on the
\r
1102 * queue. The size of the items the queue will hold was defined when the
\r
1103 * queue was created, so this many bytes will be copied from pvItemToQueue
\r
1104 * into the queue storage area.
\r
1106 * @param pxHigherPriorityTaskWoken xQueueOverwriteFromISR() will set
\r
1107 * *pxHigherPriorityTaskWoken to pdTRUE if sending to the queue caused a task
\r
1108 * to unblock, and the unblocked task has a priority higher than the currently
\r
1109 * running task. If xQueueOverwriteFromISR() sets this value to pdTRUE then
\r
1110 * a context switch should be requested before the interrupt is exited.
\r
1112 * @return xQueueOverwriteFromISR() is a macro that calls
\r
1113 * xQueueGenericSendFromISR(), and therefore has the same return values as
\r
1114 * xQueueSendToFrontFromISR(). However, pdPASS is the only value that can be
\r
1115 * returned because xQueueOverwriteFromISR() will write to the queue even when
\r
1116 * the queue is already full.
\r
1121 xQueueHandle xQueue;
\r
1123 void vFunction( void *pvParameters )
\r
1125 // Create a queue to hold one unsigned long value. It is strongly
\r
1126 // recommended *not* to use xQueueOverwriteFromISR() on queues that can
\r
1127 // contain more than one value, and doing so will trigger an assertion
\r
1128 // if configASSERT() is defined.
\r
1129 xQueue = xQueueCreate( 1, sizeof( unsigned long ) );
\r
1132 void vAnInterruptHandler( void )
\r
1134 // xHigherPriorityTaskWoken must be set to pdFALSE before it is used.
\r
1135 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
\r
1136 unsigned long ulVarToSend, ulValReceived;
\r
1138 // Write the value 10 to the queue using xQueueOverwriteFromISR().
\r
1140 xQueueOverwriteFromISR( xQueue, &ulVarToSend, &xHigherPriorityTaskWoken );
\r
1142 // The queue is full, but calling xQueueOverwriteFromISR() again will still
\r
1143 // pass because the value held in the queue will be overwritten with the
\r
1145 ulVarToSend = 100;
\r
1146 xQueueOverwriteFromISR( xQueue, &ulVarToSend, &xHigherPriorityTaskWoken );
\r
1148 // Reading from the queue will now return 100.
\r
1152 if( xHigherPrioritytaskWoken == pdTRUE )
\r
1154 // Writing to the queue caused a task to unblock and the unblocked task
\r
1155 // has a priority higher than or equal to the priority of the currently
\r
1156 // executing task (the task this interrupt interrupted). Perform a context
\r
1157 // switch so this interrupt returns directly to the unblocked task.
\r
1158 portYIELD_FROM_ISR(); // or portEND_SWITCHING_ISR() depending on the port.
\r
1162 * \defgroup xQueueOverwriteFromISR xQueueOverwriteFromISR
\r
1163 * \ingroup QueueManagement
\r
1165 #define xQueueOverwriteFromISR( xQueue, pvItemToQueue, pxHigherPriorityTaskWoken ) xQueueGenericSendFromISR( ( xQueue ), ( pvItemToQueue ), ( pxHigherPriorityTaskWoken ), queueOVERWRITE )
\r
1170 portBASE_TYPE xQueueSendFromISR(
\r
1171 xQueueHandle xQueue,
\r
1172 const void *pvItemToQueue,
\r
1173 portBASE_TYPE *pxHigherPriorityTaskWoken
\r
1177 * This is a macro that calls xQueueGenericSendFromISR(). It is included
\r
1178 * for backward compatibility with versions of FreeRTOS.org that did not
\r
1179 * include the xQueueSendToBackFromISR() and xQueueSendToFrontFromISR()
\r
1182 * Post an item to the back of a queue. It is safe to use this function from
\r
1183 * within an interrupt service routine.
\r
1185 * Items are queued by copy not reference so it is preferable to only
\r
1186 * queue small items, especially when called from an ISR. In most cases
\r
1187 * it would be preferable to store a pointer to the item being queued.
\r
1189 * @param xQueue The handle to the queue on which the item is to be posted.
\r
1191 * @param pvItemToQueue A pointer to the item that is to be placed on the
\r
1192 * queue. The size of the items the queue will hold was defined when the
\r
1193 * queue was created, so this many bytes will be copied from pvItemToQueue
\r
1194 * into the queue storage area.
\r
1196 * @param pxHigherPriorityTaskWoken xQueueSendFromISR() will set
\r
1197 * *pxHigherPriorityTaskWoken to pdTRUE if sending to the queue caused a task
\r
1198 * to unblock, and the unblocked task has a priority higher than the currently
\r
1199 * running task. If xQueueSendFromISR() sets this value to pdTRUE then
\r
1200 * a context switch should be requested before the interrupt is exited.
\r
1202 * @return pdTRUE if the data was successfully sent to the queue, otherwise
\r
1205 * Example usage for buffered IO (where the ISR can obtain more than one value
\r
1208 void vBufferISR( void )
\r
1211 portBASE_TYPE xHigherPriorityTaskWoken;
\r
1213 // We have not woken a task at the start of the ISR.
\r
1214 xHigherPriorityTaskWoken = pdFALSE;
\r
1216 // Loop until the buffer is empty.
\r
1219 // Obtain a byte from the buffer.
\r
1220 cIn = portINPUT_BYTE( RX_REGISTER_ADDRESS );
\r
1223 xQueueSendFromISR( xRxQueue, &cIn, &xHigherPriorityTaskWoken );
\r
1225 } while( portINPUT_BYTE( BUFFER_COUNT ) );
\r
1227 // Now the buffer is empty we can switch context if necessary.
\r
1228 if( xHigherPriorityTaskWoken )
\r
1230 // Actual macro used here is port specific.
\r
1231 taskYIELD_FROM_ISR ();
\r
1236 * \defgroup xQueueSendFromISR xQueueSendFromISR
\r
1237 * \ingroup QueueManagement
\r
1239 #define xQueueSendFromISR( xQueue, pvItemToQueue, pxHigherPriorityTaskWoken ) xQueueGenericSendFromISR( ( xQueue ), ( pvItemToQueue ), ( pxHigherPriorityTaskWoken ), queueSEND_TO_BACK )
\r
1244 portBASE_TYPE xQueueGenericSendFromISR(
\r
1245 xQueueHandle xQueue,
\r
1246 const void *pvItemToQueue,
\r
1247 portBASE_TYPE *pxHigherPriorityTaskWoken,
\r
1248 portBASE_TYPE xCopyPosition
\r
1252 * It is preferred that the macros xQueueSendFromISR(),
\r
1253 * xQueueSendToFrontFromISR() and xQueueSendToBackFromISR() be used in place
\r
1254 * of calling this function directly.
\r
1256 * Post an item on a queue. It is safe to use this function from within an
\r
1257 * interrupt service routine.
\r
1259 * Items are queued by copy not reference so it is preferable to only
\r
1260 * queue small items, especially when called from an ISR. In most cases
\r
1261 * it would be preferable to store a pointer to the item being queued.
\r
1263 * @param xQueue The handle to the queue on which the item is to be posted.
\r
1265 * @param pvItemToQueue A pointer to the item that is to be placed on the
\r
1266 * queue. The size of the items the queue will hold was defined when the
\r
1267 * queue was created, so this many bytes will be copied from pvItemToQueue
\r
1268 * into the queue storage area.
\r
1270 * @param pxHigherPriorityTaskWoken xQueueGenericSendFromISR() will set
\r
1271 * *pxHigherPriorityTaskWoken to pdTRUE if sending to the queue caused a task
\r
1272 * to unblock, and the unblocked task has a priority higher than the currently
\r
1273 * running task. If xQueueGenericSendFromISR() sets this value to pdTRUE then
\r
1274 * a context switch should be requested before the interrupt is exited.
\r
1276 * @param xCopyPosition Can take the value queueSEND_TO_BACK to place the
\r
1277 * item at the back of the queue, or queueSEND_TO_FRONT to place the item
\r
1278 * at the front of the queue (for high priority messages).
\r
1280 * @return pdTRUE if the data was successfully sent to the queue, otherwise
\r
1283 * Example usage for buffered IO (where the ISR can obtain more than one value
\r
1286 void vBufferISR( void )
\r
1289 portBASE_TYPE xHigherPriorityTaskWokenByPost;
\r
1291 // We have not woken a task at the start of the ISR.
\r
1292 xHigherPriorityTaskWokenByPost = pdFALSE;
\r
1294 // Loop until the buffer is empty.
\r
1297 // Obtain a byte from the buffer.
\r
1298 cIn = portINPUT_BYTE( RX_REGISTER_ADDRESS );
\r
1300 // Post each byte.
\r
1301 xQueueGenericSendFromISR( xRxQueue, &cIn, &xHigherPriorityTaskWokenByPost, queueSEND_TO_BACK );
\r
1303 } while( portINPUT_BYTE( BUFFER_COUNT ) );
\r
1305 // Now the buffer is empty we can switch context if necessary. Note that the
\r
1306 // name of the yield function required is port specific.
\r
1307 if( xHigherPriorityTaskWokenByPost )
\r
1309 taskYIELD_YIELD_FROM_ISR();
\r
1314 * \defgroup xQueueSendFromISR xQueueSendFromISR
\r
1315 * \ingroup QueueManagement
\r
1317 signed portBASE_TYPE xQueueGenericSendFromISR( xQueueHandle xQueue, const void * const pvItemToQueue, signed portBASE_TYPE *pxHigherPriorityTaskWoken, portBASE_TYPE xCopyPosition ) PRIVILEGED_FUNCTION;
\r
1322 portBASE_TYPE xQueueReceiveFromISR(
\r
1323 xQueueHandle xQueue,
\r
1325 portBASE_TYPE *pxTaskWoken
\r
1329 * Receive an item from a queue. It is safe to use this function from within an
\r
1330 * interrupt service routine.
\r
1332 * @param xQueue The handle to the queue from which the item is to be
\r
1335 * @param pvBuffer Pointer to the buffer into which the received item will
\r
1338 * @param pxTaskWoken A task may be blocked waiting for space to become
\r
1339 * available on the queue. If xQueueReceiveFromISR causes such a task to
\r
1340 * unblock *pxTaskWoken will get set to pdTRUE, otherwise *pxTaskWoken will
\r
1341 * remain unchanged.
\r
1343 * @return pdTRUE if an item was successfully received from the queue,
\r
1344 * otherwise pdFALSE.
\r
1349 xQueueHandle xQueue;
\r
1351 // Function to create a queue and post some values.
\r
1352 void vAFunction( void *pvParameters )
\r
1354 char cValueToPost;
\r
1355 const portTickType xBlockTime = ( portTickType )0xff;
\r
1357 // Create a queue capable of containing 10 characters.
\r
1358 xQueue = xQueueCreate( 10, sizeof( char ) );
\r
1361 // Failed to create the queue.
\r
1366 // Post some characters that will be used within an ISR. If the queue
\r
1367 // is full then this task will block for xBlockTime ticks.
\r
1368 cValueToPost = 'a';
\r
1369 xQueueSend( xQueue, ( void * ) &cValueToPost, xBlockTime );
\r
1370 cValueToPost = 'b';
\r
1371 xQueueSend( xQueue, ( void * ) &cValueToPost, xBlockTime );
\r
1373 // ... keep posting characters ... this task may block when the queue
\r
1376 cValueToPost = 'c';
\r
1377 xQueueSend( xQueue, ( void * ) &cValueToPost, xBlockTime );
\r
1380 // ISR that outputs all the characters received on the queue.
\r
1381 void vISR_Routine( void )
\r
1383 portBASE_TYPE xTaskWokenByReceive = pdFALSE;
\r
1386 while( xQueueReceiveFromISR( xQueue, ( void * ) &cRxedChar, &xTaskWokenByReceive) )
\r
1388 // A character was received. Output the character now.
\r
1389 vOutputCharacter( cRxedChar );
\r
1391 // If removing the character from the queue woke the task that was
\r
1392 // posting onto the queue cTaskWokenByReceive will have been set to
\r
1393 // pdTRUE. No matter how many times this loop iterates only one
\r
1394 // task will be woken.
\r
1397 if( cTaskWokenByPost != ( char ) pdFALSE;
\r
1403 * \defgroup xQueueReceiveFromISR xQueueReceiveFromISR
\r
1404 * \ingroup QueueManagement
\r
1406 signed portBASE_TYPE xQueueReceiveFromISR( xQueueHandle xQueue, const void * const pvBuffer, signed portBASE_TYPE *pxHigherPriorityTaskWoken ) PRIVILEGED_FUNCTION;
\r
1409 * Utilities to query queues that are safe to use from an ISR. These utilities
\r
1410 * should be used only from witin an ISR, or within a critical section.
\r
1412 signed portBASE_TYPE xQueueIsQueueEmptyFromISR( const xQueueHandle xQueue ) PRIVILEGED_FUNCTION;
\r
1413 signed portBASE_TYPE xQueueIsQueueFullFromISR( const xQueueHandle xQueue ) PRIVILEGED_FUNCTION;
\r
1414 unsigned portBASE_TYPE uxQueueMessagesWaitingFromISR( const xQueueHandle xQueue ) PRIVILEGED_FUNCTION;
\r
1418 * xQueueAltGenericSend() is an alternative version of xQueueGenericSend().
\r
1419 * Likewise xQueueAltGenericReceive() is an alternative version of
\r
1420 * xQueueGenericReceive().
\r
1422 * The source code that implements the alternative (Alt) API is much
\r
1423 * simpler because it executes everything from within a critical section.
\r
1424 * This is the approach taken by many other RTOSes, but FreeRTOS.org has the
\r
1425 * preferred fully featured API too. The fully featured API has more
\r
1426 * complex code that takes longer to execute, but makes much less use of
\r
1427 * critical sections. Therefore the alternative API sacrifices interrupt
\r
1428 * responsiveness to gain execution speed, whereas the fully featured API
\r
1429 * sacrifices execution speed to ensure better interrupt responsiveness.
\r
1431 signed portBASE_TYPE xQueueAltGenericSend( xQueueHandle xQueue, const void * const pvItemToQueue, portTickType xTicksToWait, portBASE_TYPE xCopyPosition );
\r
1432 signed portBASE_TYPE xQueueAltGenericReceive( xQueueHandle xQueue, void * const pvBuffer, portTickType xTicksToWait, portBASE_TYPE xJustPeeking );
\r
1433 #define xQueueAltSendToFront( xQueue, pvItemToQueue, xTicksToWait ) xQueueAltGenericSend( ( xQueue ), ( pvItemToQueue ), ( xTicksToWait ), queueSEND_TO_FRONT )
\r
1434 #define xQueueAltSendToBack( xQueue, pvItemToQueue, xTicksToWait ) xQueueAltGenericSend( ( xQueue ), ( pvItemToQueue ), ( xTicksToWait ), queueSEND_TO_BACK )
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1435 #define xQueueAltReceive( xQueue, pvBuffer, xTicksToWait ) xQueueAltGenericReceive( ( xQueue ), ( pvBuffer ), ( xTicksToWait ), pdFALSE )
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1436 #define xQueueAltPeek( xQueue, pvBuffer, xTicksToWait ) xQueueAltGenericReceive( ( xQueue ), ( pvBuffer ), ( xTicksToWait ), pdTRUE )
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1439 * The functions defined above are for passing data to and from tasks. The
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1440 * functions below are the equivalents for passing data to and from
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1443 * These functions are called from the co-routine macro implementation and
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1444 * should not be called directly from application code. Instead use the macro
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1445 * wrappers defined within croutine.h.
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1447 signed portBASE_TYPE xQueueCRSendFromISR( xQueueHandle xQueue, const void *pvItemToQueue, signed portBASE_TYPE xCoRoutinePreviouslyWoken );
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1448 signed portBASE_TYPE xQueueCRReceiveFromISR( xQueueHandle xQueue, void *pvBuffer, signed portBASE_TYPE *pxTaskWoken );
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1449 signed portBASE_TYPE xQueueCRSend( xQueueHandle xQueue, const void *pvItemToQueue, portTickType xTicksToWait );
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1450 signed portBASE_TYPE xQueueCRReceive( xQueueHandle xQueue, void *pvBuffer, portTickType xTicksToWait );
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1453 * For internal use only. Use xSemaphoreCreateMutex(),
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1454 * xSemaphoreCreateCounting() or xSemaphoreGetMutexHolder() instead of calling
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1455 * these functions directly.
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1457 xQueueHandle xQueueCreateMutex( unsigned char ucQueueType ) PRIVILEGED_FUNCTION;
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1458 xQueueHandle xQueueCreateCountingSemaphore( unsigned portBASE_TYPE uxCountValue, unsigned portBASE_TYPE uxInitialCount ) PRIVILEGED_FUNCTION;
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1459 void* xQueueGetMutexHolder( xQueueHandle xSemaphore ) PRIVILEGED_FUNCTION;
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1462 * For internal use only. Use xSemaphoreTakeMutexRecursive() or
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1463 * xSemaphoreGiveMutexRecursive() instead of calling these functions directly.
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1465 portBASE_TYPE xQueueTakeMutexRecursive( xQueueHandle xMutex, portTickType xBlockTime ) PRIVILEGED_FUNCTION;
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1466 portBASE_TYPE xQueueGiveMutexRecursive( xQueueHandle pxMutex ) PRIVILEGED_FUNCTION;
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1469 * Reset a queue back to its original empty state. pdPASS is returned if the
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1470 * queue is successfully reset. pdFAIL is returned if the queue could not be
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1471 * reset because there are tasks blocked on the queue waiting to either
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1472 * receive from the queue or send to the queue.
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1474 #define xQueueReset( xQueue ) xQueueGenericReset( xQueue, pdFALSE )
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1477 * The registry is provided as a means for kernel aware debuggers to
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1478 * locate queues, semaphores and mutexes. Call vQueueAddToRegistry() add
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1479 * a queue, semaphore or mutex handle to the registry if you want the handle
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1480 * to be available to a kernel aware debugger. If you are not using a kernel
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1481 * aware debugger then this function can be ignored.
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1483 * configQUEUE_REGISTRY_SIZE defines the maximum number of handles the
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1484 * registry can hold. configQUEUE_REGISTRY_SIZE must be greater than 0
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1485 * within FreeRTOSConfig.h for the registry to be available. Its value
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1486 * does not effect the number of queues, semaphores and mutexes that can be
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1487 * created - just the number that the registry can hold.
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1489 * @param xQueue The handle of the queue being added to the registry. This
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1490 * is the handle returned by a call to xQueueCreate(). Semaphore and mutex
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1491 * handles can also be passed in here.
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1493 * @param pcName The name to be associated with the handle. This is the
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1494 * name that the kernel aware debugger will display.
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1496 #if configQUEUE_REGISTRY_SIZE > 0
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1497 void vQueueAddToRegistry( xQueueHandle xQueue, signed char *pcName ) PRIVILEGED_FUNCTION;
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1501 * The registry is provided as a means for kernel aware debuggers to
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1502 * locate queues, semaphores and mutexes. Call vQueueAddToRegistry() add
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1503 * a queue, semaphore or mutex handle to the registry if you want the handle
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1504 * to be available to a kernel aware debugger, and vQueueUnregisterQueue() to
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1505 * remove the queue, semaphore or mutex from the register. If you are not using
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1506 * a kernel aware debugger then this function can be ignored.
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1508 * @param xQueue The handle of the queue being removed from the registry.
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1510 #if configQUEUE_REGISTRY_SIZE > 0
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1511 void vQueueUnregisterQueue( xQueueHandle xQueue ) PRIVILEGED_FUNCTION;
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1515 * Generic version of the queue creation function, which is in turn called by
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1516 * any queue, semaphore or mutex creation function or macro.
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1518 xQueueHandle xQueueGenericCreate( unsigned portBASE_TYPE uxQueueLength, unsigned portBASE_TYPE uxItemSize, unsigned char ucQueueType ) PRIVILEGED_FUNCTION;
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1521 * Queue sets provide a mechanism to allow a task to block (pend) on a read
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1522 * operation from multiple queues or semaphores simultaneously.
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1524 * See FreeRTOS/Source/Demo/Common/Minimal/QueueSet.c for an example using this
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1527 * A queue set must be explicitly created using a call to xQueueCreateSet()
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1528 * before it can be used. Once created, standard FreeRTOS queues and semaphores
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1529 * can be added to the set using calls to xQueueAddToSet().
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1530 * xQueueSelectFromSet() is then used to determine which, if any, of the queues
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1531 * or semaphores contained in the set is in a state where a queue read or
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1532 * semaphore take operation would be successful.
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1534 * Note 1: See the documentation on http://wwwFreeRTOS.org/RTOS-queue-sets.html
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1535 * for reasons why queue sets are very rarely needed in practice as there are
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1536 * simpler methods of blocking on multiple objects.
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1538 * Note 2: Blocking on a queue set that contains a mutex will not cause the
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1539 * mutex holder to inherit the priority of the blocked task.
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1541 * Note 3: An additional 4 bytes of RAM is required for each space in a every
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1542 * queue added to a queue set. Therefore counting semaphores that have a high
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1543 * maximum count value should not be added to a queue set.
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1545 * Note 4: A receive (in the case of a queue) or take (in the case of a
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1546 * semaphore) operation must not be performed on a member of a queue set unless
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1547 * a call to xQueueSelectFromSet() has first returned a handle to that set member.
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1549 * @param uxEventQueueLength Queue sets store events that occur on
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1550 * the queues and semaphores contained in the set. uxEventQueueLength specifies
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1551 * the maximum number of events that can be queued at once. To be absolutely
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1552 * certain that events are not lost uxEventQueueLength should be set to the
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1553 * total sum of the length of the queues added to the set, where binary
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1554 * semaphores and mutexes have a length of 1, and counting semaphores have a
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1555 * length set by their maximum count value. Examples:
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1556 * + If a queue set is to hold a queue of length 5, another queue of length 12,
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1557 * and a binary semaphore, then uxEventQueueLength should be set to
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1558 * (5 + 12 + 1), or 18.
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1559 * + If a queue set is to hold three binary semaphores then uxEventQueueLength
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1560 * should be set to (1 + 1 + 1 ), or 3.
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1561 * + If a queue set is to hold a counting semaphore that has a maximum count of
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1562 * 5, and a counting semaphore that has a maximum count of 3, then
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1563 * uxEventQueueLength should be set to (5 + 3), or 8.
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1565 * @return If the queue set is created successfully then a handle to the created
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1566 * queue set is returned. Otherwise NULL is returned.
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1568 xQueueSetHandle xQueueCreateSet( unsigned portBASE_TYPE uxEventQueueLength ) PRIVILEGED_FUNCTION;
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1571 * Adds a queue or semaphore to a queue set that was previously created by a
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1572 * call to xQueueCreateSet().
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1574 * See FreeRTOS/Source/Demo/Common/Minimal/QueueSet.c for an example using this
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1577 * Note 1: A receive (in the case of a queue) or take (in the case of a
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1578 * semaphore) operation must not be performed on a member of a queue set unless
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1579 * a call to xQueueSelectFromSet() has first returned a handle to that set member.
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1581 * @param xQueueOrSemaphore The handle of the queue or semaphore being added to
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1582 * the queue set (cast to an xQueueSetMemberHandle type).
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1584 * @param xQueueSet The handle of the queue set to which the queue or semaphore
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1587 * @return If the queue or semaphore was successfully added to the queue set
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1588 * then pdPASS is returned. If the queue could not be successfully added to the
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1589 * queue set because it is already a member of a different queue set then pdFAIL
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1592 portBASE_TYPE xQueueAddToSet( xQueueSetMemberHandle xQueueOrSemaphore, xQueueSetHandle xQueueSet ) PRIVILEGED_FUNCTION;
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1595 * Removes a queue or semaphore from a queue set. A queue or semaphore can only
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1596 * be removed from a set if the queue or semaphore is empty.
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1598 * See FreeRTOS/Source/Demo/Common/Minimal/QueueSet.c for an example using this
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1601 * @param xQueueOrSemaphore The handle of the queue or semaphore being removed
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1602 * from the queue set (cast to an xQueueSetMemberHandle type).
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1604 * @param xQueueSet The handle of the queue set in which the queue or semaphore
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1607 * @return If the queue or semaphore was successfully removed from the queue set
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1608 * then pdPASS is returned. If the queue was not in the queue set, or the
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1609 * queue (or semaphore) was not empty, then pdFAIL is returned.
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1611 portBASE_TYPE xQueueRemoveFromSet( xQueueSetMemberHandle xQueueOrSemaphore, xQueueSetHandle xQueueSet ) PRIVILEGED_FUNCTION;
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1614 * xQueueSelectFromSet() selects from the members of a queue set a queue or
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1615 * semaphore that either contains data (in the case of a queue) or is available
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1616 * to take (in the case of a semaphore). xQueueSelectFromSet() effectively
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1617 * allows a task to block (pend) on a read operation on all the queues and
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1618 * semaphores in a queue set simultaneously.
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1620 * See FreeRTOS/Source/Demo/Common/Minimal/QueueSet.c for an example using this
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1623 * Note 1: See the documentation on http://wwwFreeRTOS.org/RTOS-queue-sets.html
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1624 * for reasons why queue sets are very rarely needed in practice as there are
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1625 * simpler methods of blocking on multiple objects.
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1627 * Note 2: Blocking on a queue set that contains a mutex will not cause the
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1628 * mutex holder to inherit the priority of the blocked task.
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1630 * Note 3: A receive (in the case of a queue) or take (in the case of a
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1631 * semaphore) operation must not be performed on a member of a queue set unless
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1632 * a call to xQueueSelectFromSet() has first returned a handle to that set member.
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1634 * @param xQueueSet The queue set on which the task will (potentially) block.
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1636 * @param xBlockTimeTicks The maximum time, in ticks, that the calling task will
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1637 * remain in the Blocked state (with other tasks executing) to wait for a member
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1638 * of the queue set to be ready for a successful queue read or semaphore take
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1641 * @return xQueueSelectFromSet() will return the handle of a queue (cast to
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1642 * a xQueueSetMemberHandle type) contained in the queue set that contains data,
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1643 * or the handle of a semaphore (cast to a xQueueSetMemberHandle type) contained
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1644 * in the queue set that is available, or NULL if no such queue or semaphore
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1645 * exists before before the specified block time expires.
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1647 xQueueSetMemberHandle xQueueSelectFromSet( xQueueSetHandle xQueueSet, portTickType xBlockTimeTicks ) PRIVILEGED_FUNCTION;
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1650 * A version of xQueueSelectFromSet() that can be used from an ISR.
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1652 xQueueSetMemberHandle xQueueSelectFromSetFromISR( xQueueSetHandle xQueueSet ) PRIVILEGED_FUNCTION;
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1654 /* Not public API functions. */
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1655 void vQueueWaitForMessageRestricted( xQueueHandle xQueue, portTickType xTicksToWait ) PRIVILEGED_FUNCTION;
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1656 portBASE_TYPE xQueueGenericReset( xQueueHandle xQueue, portBASE_TYPE xNewQueue ) PRIVILEGED_FUNCTION;
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1657 void vQueueSetQueueNumber( xQueueHandle xQueue, unsigned char ucQueueNumber ) PRIVILEGED_FUNCTION;
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1658 unsigned char ucQueueGetQueueNumber( xQueueHandle xQueue ) PRIVILEGED_FUNCTION;
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1659 unsigned char ucQueueGetQueueType( xQueueHandle xQueue ) PRIVILEGED_FUNCTION;
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1662 #ifdef __cplusplus
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1666 #endif /* QUEUE_H */
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projects / freertos / blob