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diff --git a/freertos/include/queue.h b/freertos/include/queue.h new file mode 100644 index 0000000..30be360 --- /dev/null +++ b/freertos/include/queue.h @@ -0,0 +1,1798 @@ +/* + FreeRTOS V9.0.0 - Copyright (C) 2016 Real Time Engineers Ltd. + All rights reserved + + VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION. + + This file is part of the FreeRTOS distribution. + + FreeRTOS is free software; you can redistribute it and/or modify it under + the terms of the GNU General Public License (version 2) as published by the + Free Software Foundation >>>> AND MODIFIED BY <<<< the FreeRTOS exception. + + *************************************************************************** + >>! NOTE: The modification to the GPL is included to allow you to !<< + >>! distribute a combined work that includes FreeRTOS without being !<< + >>! obliged to provide the source code for proprietary components !<< + >>! outside of the FreeRTOS kernel. !<< + *************************************************************************** + + FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY + WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS + FOR A PARTICULAR PURPOSE. Full license text is available on the following + link: http://www.freertos.org/a00114.html + + *************************************************************************** + * * + * FreeRTOS provides completely free yet professionally developed, * + * robust, strictly quality controlled, supported, and cross * + * platform software that is more than just the market leader, it * + * is the industry's de facto standard. * + * * + * Help yourself get started quickly while simultaneously helping * + * to support the FreeRTOS project by purchasing a FreeRTOS * + * tutorial book, reference manual, or both: * + * http://www.FreeRTOS.org/Documentation * + * * + *************************************************************************** + + http://www.FreeRTOS.org/FAQHelp.html - Having a problem? Start by reading + the FAQ page "My application does not run, what could be wrong?". Have you + defined configASSERT()? + + http://www.FreeRTOS.org/support - In return for receiving this top quality + embedded software for free we request you assist our global community by + participating in the support forum. + + http://www.FreeRTOS.org/training - Investing in training allows your team to + be as productive as possible as early as possible. Now you can receive + FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers + Ltd, and the world's leading authority on the world's leading RTOS. + + http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products, + including FreeRTOS+Trace - an indispensable productivity tool, a DOS + compatible FAT file system, and our tiny thread aware UDP/IP stack. + + http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate. + Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS. + + http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High + Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS + licenses offer ticketed support, indemnification and commercial middleware. + + http://www.SafeRTOS.com - High Integrity Systems also provide a safety + engineered and independently SIL3 certified version for use in safety and + mission critical applications that require provable dependability. + + 1 tab == 4 spaces! +*/ + + +#ifndef QUEUE_H +#define QUEUE_H + +#ifndef INC_FREERTOS_H + #error "include FreeRTOS.h" must appear in source files before "include queue.h" +#endif + +#ifdef __cplusplus +extern "C" { +#endif + + +/** + * Type by which queues are referenced. For example, a call to xQueueCreate() + * returns an QueueHandle_t variable that can then be used as a parameter to + * xQueueSend(), xQueueReceive(), etc. + */ +typedef void * QueueHandle_t; + +/** + * Type by which queue sets are referenced. For example, a call to + * xQueueCreateSet() returns an xQueueSet variable that can then be used as a + * parameter to xQueueSelectFromSet(), xQueueAddToSet(), etc. + */ +typedef void * QueueSetHandle_t; + +/** + * Queue sets can contain both queues and semaphores, so the + * QueueSetMemberHandle_t is defined as a type to be used where a parameter or + * return value can be either an QueueHandle_t or an SemaphoreHandle_t. + */ +typedef void * QueueSetMemberHandle_t; + +/* For internal use only. */ +#define queueSEND_TO_BACK ( ( BaseType_t ) 0 ) +#define queueSEND_TO_FRONT ( ( BaseType_t ) 1 ) +#define queueOVERWRITE ( ( BaseType_t ) 2 ) + +/* For internal use only. These definitions *must* match those in queue.c. */ +#define queueQUEUE_TYPE_BASE ( ( uint8_t ) 0U ) +#define queueQUEUE_TYPE_SET ( ( uint8_t ) 0U ) +#define queueQUEUE_TYPE_MUTEX ( ( uint8_t ) 1U ) +#define queueQUEUE_TYPE_COUNTING_SEMAPHORE ( ( uint8_t ) 2U ) +#define queueQUEUE_TYPE_BINARY_SEMAPHORE ( ( uint8_t ) 3U ) +#define queueQUEUE_TYPE_RECURSIVE_MUTEX ( ( uint8_t ) 4U ) + +/** + * queue. h + * <pre> + QueueHandle_t xQueueCreate( + UBaseType_t uxQueueLength, + UBaseType_t uxItemSize + ); + * </pre> + * + * Creates a new queue instance, and returns a handle by which the new queue + * can be referenced. + * + * Internally, within the FreeRTOS implementation, queues use two blocks of + * memory. The first block is used to hold the queue's data structures. The + * second block is used to hold items placed into the queue. If a queue is + * created using xQueueCreate() then both blocks of memory are automatically + * dynamically allocated inside the xQueueCreate() function. (see + * http://www.freertos.org/a00111.html). If a queue is created using + * xQueueCreateStatic() then the application writer must provide the memory that + * will get used by the queue. xQueueCreateStatic() therefore allows a queue to + * be created without using any dynamic memory allocation. + * + * http://www.FreeRTOS.org/Embedded-RTOS-Queues.html + * + * @param uxQueueLength The maximum number of items that the queue can contain. + * + * @param uxItemSize The number of bytes each item in the queue will require. + * Items are queued by copy, not by reference, so this is the number of bytes + * that will be copied for each posted item. Each item on the queue must be + * the same size. + * + * @return If the queue is successfully create then a handle to the newly + * created queue is returned. If the queue cannot be created then 0 is + * returned. + * + * Example usage: + <pre> + struct AMessage + { + char ucMessageID; + char ucData[ 20 ]; + }; + + void vATask( void *pvParameters ) + { + QueueHandle_t xQueue1, xQueue2; + + // Create a queue capable of containing 10 uint32_t values. + xQueue1 = xQueueCreate( 10, sizeof( uint32_t ) ); + if( xQueue1 == 0 ) + { + // Queue was not created and must not be used. + } + + // Create a queue capable of containing 10 pointers to AMessage structures. + // These should be passed by pointer as they contain a lot of data. + xQueue2 = xQueueCreate( 10, sizeof( struct AMessage * ) ); + if( xQueue2 == 0 ) + { + // Queue was not created and must not be used. + } + + // ... Rest of task code. + } + </pre> + * \defgroup xQueueCreate xQueueCreate + * \ingroup QueueManagement + */ +#if( configSUPPORT_DYNAMIC_ALLOCATION == 1 ) + #define xQueueCreate( uxQueueLength, uxItemSize ) xQueueGenericCreate( ( uxQueueLength ), ( uxItemSize ), ( queueQUEUE_TYPE_BASE ) ) +#endif + +/** + * queue. h + * <pre> + QueueHandle_t xQueueCreateStatic( + UBaseType_t uxQueueLength, + UBaseType_t uxItemSize, + uint8_t *pucQueueStorageBuffer, + StaticQueue_t *pxQueueBuffer + ); + * </pre> + * + * Creates a new queue instance, and returns a handle by which the new queue + * can be referenced. + * + * Internally, within the FreeRTOS implementation, queues use two blocks of + * memory. The first block is used to hold the queue's data structures. The + * second block is used to hold items placed into the queue. If a queue is + * created using xQueueCreate() then both blocks of memory are automatically + * dynamically allocated inside the xQueueCreate() function. (see + * http://www.freertos.org/a00111.html). If a queue is created using + * xQueueCreateStatic() then the application writer must provide the memory that + * will get used by the queue. xQueueCreateStatic() therefore allows a queue to + * be created without using any dynamic memory allocation. + * + * http://www.FreeRTOS.org/Embedded-RTOS-Queues.html + * + * @param uxQueueLength The maximum number of items that the queue can contain. + * + * @param uxItemSize The number of bytes each item in the queue will require. + * Items are queued by copy, not by reference, so this is the number of bytes + * that will be copied for each posted item. Each item on the queue must be + * the same size. + * + * @param pucQueueStorageBuffer If uxItemSize is not zero then + * pucQueueStorageBuffer must point to a uint8_t array that is at least large + * enough to hold the maximum number of items that can be in the queue at any + * one time - which is ( uxQueueLength * uxItemsSize ) bytes. If uxItemSize is + * zero then pucQueueStorageBuffer can be NULL. + * + * @param pxQueueBuffer Must point to a variable of type StaticQueue_t, which + * will be used to hold the queue's data structure. + * + * @return If the queue is created then a handle to the created queue is + * returned. If pxQueueBuffer is NULL then NULL is returned. + * + * Example usage: + <pre> + struct AMessage + { + char ucMessageID; + char ucData[ 20 ]; + }; + + #define QUEUE_LENGTH 10 + #define ITEM_SIZE sizeof( uint32_t ) + + // xQueueBuffer will hold the queue structure. + StaticQueue_t xQueueBuffer; + + // ucQueueStorage will hold the items posted to the queue. Must be at least + // [(queue length) * ( queue item size)] bytes long. + uint8_t ucQueueStorage[ QUEUE_LENGTH * ITEM_SIZE ]; + + void vATask( void *pvParameters ) + { + QueueHandle_t xQueue1; + + // Create a queue capable of containing 10 uint32_t values. + xQueue1 = xQueueCreate( QUEUE_LENGTH, // The number of items the queue can hold. + ITEM_SIZE // The size of each item in the queue + &( ucQueueStorage[ 0 ] ), // The buffer that will hold the items in the queue. + &xQueueBuffer ); // The buffer that will hold the queue structure. + + // The queue is guaranteed to be created successfully as no dynamic memory + // allocation is used. Therefore xQueue1 is now a handle to a valid queue. + + // ... Rest of task code. + } + </pre> + * \defgroup xQueueCreateStatic xQueueCreateStatic + * \ingroup QueueManagement + */ +#if( configSUPPORT_STATIC_ALLOCATION == 1 ) + #define xQueueCreateStatic( uxQueueLength, uxItemSize, pucQueueStorage, pxQueueBuffer ) xQueueGenericCreateStatic( ( uxQueueLength ), ( uxItemSize ), ( pucQueueStorage ), ( pxQueueBuffer ), ( queueQUEUE_TYPE_BASE ) ) +#endif /* configSUPPORT_STATIC_ALLOCATION */ + +/** + * queue. h + * <pre> + BaseType_t xQueueSendToToFront( + QueueHandle_t xQueue, + const void *pvItemToQueue, + TickType_t xTicksToWait + ); + * </pre> + * + * This is a macro that calls xQueueGenericSend(). + * + * Post an item to the front of a queue. The item is queued by copy, not by + * reference. This function must not be called from an interrupt service + * routine. See xQueueSendFromISR () for an alternative which may be used + * in an ISR. + * + * @param xQueue The handle to the queue on which the item is to be posted. + * + * @param pvItemToQueue A pointer to the item that is to be placed on the + * queue. The size of the items the queue will hold was defined when the + * queue was created, so this many bytes will be copied from pvItemToQueue + * into the queue storage area. + * + * @param xTicksToWait The maximum amount of time the task should block + * waiting for space to become available on the queue, should it already + * be full. The call will return immediately if this is set to 0 and the + * queue is full. The time is defined in tick periods so the constant + * portTICK_PERIOD_MS should be used to convert to real time if this is required. + * + * @return pdTRUE if the item was successfully posted, otherwise errQUEUE_FULL. + * + * Example usage: + <pre> + struct AMessage + { + char ucMessageID; + char ucData[ 20 ]; + } xMessage; + + uint32_t ulVar = 10UL; + + void vATask( void *pvParameters ) + { + QueueHandle_t xQueue1, xQueue2; + struct AMessage *pxMessage; + + // Create a queue capable of containing 10 uint32_t values. + xQueue1 = xQueueCreate( 10, sizeof( uint32_t ) ); + + // Create a queue capable of containing 10 pointers to AMessage structures. + // These should be passed by pointer as they contain a lot of data. + xQueue2 = xQueueCreate( 10, sizeof( struct AMessage * ) ); + + // ... + + if( xQueue1 != 0 ) + { + // Send an uint32_t. Wait for 10 ticks for space to become + // available if necessary. + if( xQueueSendToFront( xQueue1, ( void * ) &ulVar, ( TickType_t ) 10 ) != pdPASS ) + { + // Failed to post the message, even after 10 ticks. + } + } + + if( xQueue2 != 0 ) + { + // Send a pointer to a struct AMessage object. Don't block if the + // queue is already full. + pxMessage = & xMessage; + xQueueSendToFront( xQueue2, ( void * ) &pxMessage, ( TickType_t ) 0 ); + } + + // ... Rest of task code. + } + </pre> + * \defgroup xQueueSend xQueueSend + * \ingroup QueueManagement + */ +#define xQueueSendToFront( xQueue, pvItemToQueue, xTicksToWait ) xQueueGenericSend( ( xQueue ), ( pvItemToQueue ), ( xTicksToWait ), queueSEND_TO_FRONT ) + +/** + * queue. h + * <pre> + BaseType_t xQueueSendToBack( + QueueHandle_t xQueue, + const void *pvItemToQueue, + TickType_t xTicksToWait + ); + * </pre> + * + * This is a macro that calls xQueueGenericSend(). + * + * Post an item to the back of a queue. The item is queued by copy, not by + * reference. This function must not be called from an interrupt service + * routine. See xQueueSendFromISR () for an alternative which may be used + * in an ISR. + * + * @param xQueue The handle to the queue on which the item is to be posted. + * + * @param pvItemToQueue A pointer to the item that is to be placed on the + * queue. The size of the items the queue will hold was defined when the + * queue was created, so this many bytes will be copied from pvItemToQueue + * into the queue storage area. + * + * @param xTicksToWait The maximum amount of time the task should block + * waiting for space to become available on the queue, should it already + * be full. The call will return immediately if this is set to 0 and the queue + * is full. The time is defined in tick periods so the constant + * portTICK_PERIOD_MS should be used to convert to real time if this is required. + * + * @return pdTRUE if the item was successfully posted, otherwise errQUEUE_FULL. + * + * Example usage: + <pre> + struct AMessage + { + char ucMessageID; + char ucData[ 20 ]; + } xMessage; + + uint32_t ulVar = 10UL; + + void vATask( void *pvParameters ) + { + QueueHandle_t xQueue1, xQueue2; + struct AMessage *pxMessage; + + // Create a queue capable of containing 10 uint32_t values. + xQueue1 = xQueueCreate( 10, sizeof( uint32_t ) ); + + // Create a queue capable of containing 10 pointers to AMessage structures. + // These should be passed by pointer as they contain a lot of data. + xQueue2 = xQueueCreate( 10, sizeof( struct AMessage * ) ); + + // ... + + if( xQueue1 != 0 ) + { + // Send an uint32_t. Wait for 10 ticks for space to become + // available if necessary. + if( xQueueSendToBack( xQueue1, ( void * ) &ulVar, ( TickType_t ) 10 ) != pdPASS ) + { + // Failed to post the message, even after 10 ticks. + } + } + + if( xQueue2 != 0 ) + { + // Send a pointer to a struct AMessage object. Don't block if the + // queue is already full. + pxMessage = & xMessage; + xQueueSendToBack( xQueue2, ( void * ) &pxMessage, ( TickType_t ) 0 ); + } + + // ... Rest of task code. + } + </pre> + * \defgroup xQueueSend xQueueSend + * \ingroup QueueManagement + */ +#define xQueueSendToBack( xQueue, pvItemToQueue, xTicksToWait ) xQueueGenericSend( ( xQueue ), ( pvItemToQueue ), ( xTicksToWait ), queueSEND_TO_BACK ) + +/** + * queue. h + * <pre> + BaseType_t xQueueSend( + QueueHandle_t xQueue, + const void * pvItemToQueue, + TickType_t xTicksToWait + ); + * </pre> + * + * This is a macro that calls xQueueGenericSend(). It is included for + * backward compatibility with versions of FreeRTOS.org that did not + * include the xQueueSendToFront() and xQueueSendToBack() macros. It is + * equivalent to xQueueSendToBack(). + * + * Post an item on a queue. The item is queued by copy, not by reference. + * This function must not be called from an interrupt service routine. + * See xQueueSendFromISR () for an alternative which may be used in an ISR. + * + * @param xQueue The handle to the queue on which the item is to be posted. + * + * @param pvItemToQueue A pointer to the item that is to be placed on the + * queue. The size of the items the queue will hold was defined when the + * queue was created, so this many bytes will be copied from pvItemToQueue + * into the queue storage area. + * + * @param xTicksToWait The maximum amount of time the task should block + * waiting for space to become available on the queue, should it already + * be full. The call will return immediately if this is set to 0 and the + * queue is full. The time is defined in tick periods so the constant + * portTICK_PERIOD_MS should be used to convert to real time if this is required. + * + * @return pdTRUE if the item was successfully posted, otherwise errQUEUE_FULL. + * + * Example usage: + <pre> + struct AMessage + { + char ucMessageID; + char ucData[ 20 ]; + } xMessage; + + uint32_t ulVar = 10UL; + + void vATask( void *pvParameters ) + { + QueueHandle_t xQueue1, xQueue2; + struct AMessage *pxMessage; + + // Create a queue capable of containing 10 uint32_t values. + xQueue1 = xQueueCreate( 10, sizeof( uint32_t ) ); + + // Create a queue capable of containing 10 pointers to AMessage structures. + // These should be passed by pointer as they contain a lot of data. + xQueue2 = xQueueCreate( 10, sizeof( struct AMessage * ) ); + + // ... + + if( xQueue1 != 0 ) + { + // Send an uint32_t. Wait for 10 ticks for space to become + // available if necessary. + if( xQueueSend( xQueue1, ( void * ) &ulVar, ( TickType_t ) 10 ) != pdPASS ) + { + // Failed to post the message, even after 10 ticks. + } + } + + if( xQueue2 != 0 ) + { + // Send a pointer to a struct AMessage object. Don't block if the + // queue is already full. + pxMessage = & xMessage; + xQueueSend( xQueue2, ( void * ) &pxMessage, ( TickType_t ) 0 ); + } + + // ... Rest of task code. + } + </pre> + * \defgroup xQueueSend xQueueSend + * \ingroup QueueManagement + */ +#define xQueueSend( xQueue, pvItemToQueue, xTicksToWait ) xQueueGenericSend( ( xQueue ), ( pvItemToQueue ), ( xTicksToWait ), queueSEND_TO_BACK ) + +/** + * queue. h + * <pre> + BaseType_t xQueueOverwrite( + QueueHandle_t xQueue, + const void * pvItemToQueue + ); + * </pre> + * + * Only for use with queues that have a length of one - so the queue is either + * empty or full. + * + * Post an item on a queue. If the queue is already full then overwrite the + * value held in the queue. The item is queued by copy, not by reference. + * + * This function must not be called from an interrupt service routine. + * See xQueueOverwriteFromISR () for an alternative which may be used in an ISR. + * + * @param xQueue The handle of the queue to which the data is being sent. + * + * @param pvItemToQueue A pointer to the item that is to be placed on the + * queue. The size of the items the queue will hold was defined when the + * queue was created, so this many bytes will be copied from pvItemToQueue + * into the queue storage area. + * + * @return xQueueOverwrite() is a macro that calls xQueueGenericSend(), and + * therefore has the same return values as xQueueSendToFront(). However, pdPASS + * is the only value that can be returned because xQueueOverwrite() will write + * to the queue even when the queue is already full. + * + * Example usage: + <pre> + + void vFunction( void *pvParameters ) + { + QueueHandle_t xQueue; + uint32_t ulVarToSend, ulValReceived; + + // Create a queue to hold one uint32_t value. It is strongly + // recommended *not* to use xQueueOverwrite() on queues that can + // contain more than one value, and doing so will trigger an assertion + // if configASSERT() is defined. + xQueue = xQueueCreate( 1, sizeof( uint32_t ) ); + + // Write the value 10 to the queue using xQueueOverwrite(). + ulVarToSend = 10; + xQueueOverwrite( xQueue, &ulVarToSend ); + + // Peeking the queue should now return 10, but leave the value 10 in + // the queue. A block time of zero is used as it is known that the + // queue holds a value. + ulValReceived = 0; + xQueuePeek( xQueue, &ulValReceived, 0 ); + + if( ulValReceived != 10 ) + { + // Error unless the item was removed by a different task. + } + + // The queue is still full. Use xQueueOverwrite() to overwrite the + // value held in the queue with 100. + ulVarToSend = 100; + xQueueOverwrite( xQueue, &ulVarToSend ); + + // This time read from the queue, leaving the queue empty once more. + // A block time of 0 is used again. + xQueueReceive( xQueue, &ulValReceived, 0 ); + + // The value read should be the last value written, even though the + // queue was already full when the value was written. + if( ulValReceived != 100 ) + { + // Error! + } + + // ... +} + </pre> + * \defgroup xQueueOverwrite xQueueOverwrite + * \ingroup QueueManagement + */ +#define xQueueOverwrite( xQueue, pvItemToQueue ) xQueueGenericSend( ( xQueue ), ( pvItemToQueue ), 0, queueOVERWRITE ) + + +/** + * queue. h + * <pre> + BaseType_t xQueueGenericSend( + QueueHandle_t xQueue, + const void * pvItemToQueue, + TickType_t xTicksToWait + BaseType_t xCopyPosition + ); + * </pre> + * + * It is preferred that the macros xQueueSend(), xQueueSendToFront() and + * xQueueSendToBack() are used in place of calling this function directly. + * + * Post an item on a queue. The item is queued by copy, not by reference. + * This function must not be called from an interrupt service routine. + * See xQueueSendFromISR () for an alternative which may be used in an ISR. + * + * @param xQueue The handle to the queue on which the item is to be posted. + * + * @param pvItemToQueue A pointer to the item that is to be placed on the + * queue. The size of the items the queue will hold was defined when the + * queue was created, so this many bytes will be copied from pvItemToQueue + * into the queue storage area. + * + * @param xTicksToWait The maximum amount of time the task should block + * waiting for space to become available on the queue, should it already + * be full. The call will return immediately if this is set to 0 and the + * queue is full. The time is defined in tick periods so the constant + * portTICK_PERIOD_MS should be used to convert to real time if this is required. + * + * @param xCopyPosition Can take the value queueSEND_TO_BACK to place the + * item at the back of the queue, or queueSEND_TO_FRONT to place the item + * at the front of the queue (for high priority messages). + * + * @return pdTRUE if the item was successfully posted, otherwise errQUEUE_FULL. + * + * Example usage: + <pre> + struct AMessage + { + char ucMessageID; + char ucData[ 20 ]; + } xMessage; + + uint32_t ulVar = 10UL; + + void vATask( void *pvParameters ) + { + QueueHandle_t xQueue1, xQueue2; + struct AMessage *pxMessage; + + // Create a queue capable of containing 10 uint32_t values. + xQueue1 = xQueueCreate( 10, sizeof( uint32_t ) ); + + // Create a queue capable of containing 10 pointers to AMessage structures. + // These should be passed by pointer as they contain a lot of data. + xQueue2 = xQueueCreate( 10, sizeof( struct AMessage * ) ); + + // ... + + if( xQueue1 != 0 ) + { + // Send an uint32_t. Wait for 10 ticks for space to become + // available if necessary. + if( xQueueGenericSend( xQueue1, ( void * ) &ulVar, ( TickType_t ) 10, queueSEND_TO_BACK ) != pdPASS ) + { + // Failed to post the message, even after 10 ticks. + } + } + + if( xQueue2 != 0 ) + { + // Send a pointer to a struct AMessage object. Don't block if the + // queue is already full. + pxMessage = & xMessage; + xQueueGenericSend( xQueue2, ( void * ) &pxMessage, ( TickType_t ) 0, queueSEND_TO_BACK ); + } + + // ... Rest of task code. + } + </pre> + * \defgroup xQueueSend xQueueSend + * \ingroup QueueManagement + */ +BaseType_t xQueueGenericSend( QueueHandle_t xQueue, const void * const pvItemToQueue, TickType_t xTicksToWait, const BaseType_t xCopyPosition ) PRIVILEGED_FUNCTION; + +/** + * queue. h + * <pre> + BaseType_t xQueuePeek( + QueueHandle_t xQueue, + void *pvBuffer, + TickType_t xTicksToWait + );</pre> + * + * This is a macro that calls the xQueueGenericReceive() function. + * + * Receive an item from a queue without removing the item from the queue. + * The item is received by copy so a buffer of adequate size must be + * provided. The number of bytes copied into the buffer was defined when + * the queue was created. + * + * Successfully received items remain on the queue so will be returned again + * by the next call, or a call to xQueueReceive(). + * + * This macro must not be used in an interrupt service routine. See + * xQueuePeekFromISR() for an alternative that can be called from an interrupt + * service routine. + * + * @param xQueue The handle to the queue from which the item is to be + * received. + * + * @param pvBuffer Pointer to the buffer into which the received item will + * be copied. + * + * @param xTicksToWait The maximum amount of time the task should block + * waiting for an item to receive should the queue be empty at the time + * of the call. The time is defined in tick periods so the constant + * portTICK_PERIOD_MS should be used to convert to real time if this is required. + * xQueuePeek() will return immediately if xTicksToWait is 0 and the queue + * is empty. + * + * @return pdTRUE if an item was successfully received from the queue, + * otherwise pdFALSE. + * + * Example usage: + <pre> + struct AMessage + { + char ucMessageID; + char ucData[ 20 ]; + } xMessage; + + QueueHandle_t xQueue; + + // Task to create a queue and post a value. + void vATask( void *pvParameters ) + { + struct AMessage *pxMessage; + + // Create a queue capable of containing 10 pointers to AMessage structures. + // These should be passed by pointer as they contain a lot of data. + xQueue = xQueueCreate( 10, sizeof( struct AMessage * ) ); + if( xQueue == 0 ) + { + // Failed to create the queue. + } + + // ... + + // Send a pointer to a struct AMessage object. Don't block if the + // queue is already full. + pxMessage = & xMessage; + xQueueSend( xQueue, ( void * ) &pxMessage, ( TickType_t ) 0 ); + + // ... Rest of task code. + } + + // Task to peek the data from the queue. + void vADifferentTask( void *pvParameters ) + { + struct AMessage *pxRxedMessage; + + if( xQueue != 0 ) + { + // Peek a message on the created queue. Block for 10 ticks if a + // message is not immediately available. + if( xQueuePeek( xQueue, &( pxRxedMessage ), ( TickType_t ) 10 ) ) + { + // pcRxedMessage now points to the struct AMessage variable posted + // by vATask, but the item still remains on the queue. + } + } + + // ... Rest of task code. + } + </pre> + * \defgroup xQueueReceive xQueueReceive + * \ingroup QueueManagement + */ +#define xQueuePeek( xQueue, pvBuffer, xTicksToWait ) xQueueGenericReceive( ( xQueue ), ( pvBuffer ), ( xTicksToWait ), pdTRUE ) + +/** + * queue. h + * <pre> + BaseType_t xQueuePeekFromISR( + QueueHandle_t xQueue, + void *pvBuffer, + );</pre> + * + * A version of xQueuePeek() that can be called from an interrupt service + * routine (ISR). + * + * Receive an item from a queue without removing the item from the queue. + * The item is received by copy so a buffer of adequate size must be + * provided. The number of bytes copied into the buffer was defined when + * the queue was created. + * + * Successfully received items remain on the queue so will be returned again + * by the next call, or a call to xQueueReceive(). + * + * @param xQueue The handle to the queue from which the item is to be + * received. + * + * @param pvBuffer Pointer to the buffer into which the received item will + * be copied. + * + * @return pdTRUE if an item was successfully received from the queue, + * otherwise pdFALSE. + * + * \defgroup xQueuePeekFromISR xQueuePeekFromISR + * \ingroup QueueManagement + */ +BaseType_t xQueuePeekFromISR( QueueHandle_t xQueue, void * const pvBuffer ) PRIVILEGED_FUNCTION; + +/** + * queue. h + * <pre> + BaseType_t xQueueReceive( + QueueHandle_t xQueue, + void *pvBuffer, + TickType_t xTicksToWait + );</pre> + * + * This is a macro that calls the xQueueGenericReceive() function. + * + * Receive an item from a queue. The item is received by copy so a buffer of + * adequate size must be provided. The number of bytes copied into the buffer + * was defined when the queue was created. + * + * Successfully received items are removed from the queue. + * + * This function must not be used in an interrupt service routine. See + * xQueueReceiveFromISR for an alternative that can. + * + * @param xQueue The handle to the queue from which the item is to be + * received. + * + * @param pvBuffer Pointer to the buffer into which the received item will + * be copied. + * + * @param xTicksToWait The maximum amount of time the task should block + * waiting for an item to receive should the queue be empty at the time + * of the call. xQueueReceive() will return immediately if xTicksToWait + * is zero and the queue is empty. The time is defined in tick periods so the + * constant portTICK_PERIOD_MS should be used to convert to real time if this is + * required. + * + * @return pdTRUE if an item was successfully received from the queue, + * otherwise pdFALSE. + * + * Example usage: + <pre> + struct AMessage + { + char ucMessageID; + char ucData[ 20 ]; + } xMessage; + + QueueHandle_t xQueue; + + // Task to create a queue and post a value. + void vATask( void *pvParameters ) + { + struct AMessage *pxMessage; + + // Create a queue capable of containing 10 pointers to AMessage structures. + // These should be passed by pointer as they contain a lot of data. + xQueue = xQueueCreate( 10, sizeof( struct AMessage * ) ); + if( xQueue == 0 ) + { + // Failed to create the queue. + } + + // ... + + // Send a pointer to a struct AMessage object. Don't block if the + // queue is already full. + pxMessage = & xMessage; + xQueueSend( xQueue, ( void * ) &pxMessage, ( TickType_t ) 0 ); + + // ... Rest of task code. + } + + // Task to receive from the queue. + void vADifferentTask( void *pvParameters ) + { + struct AMessage *pxRxedMessage; + + if( xQueue != 0 ) + { + // Receive a message on the created queue. Block for 10 ticks if a + // message is not immediately available. + if( xQueueReceive( xQueue, &( pxRxedMessage ), ( TickType_t ) 10 ) ) + { + // pcRxedMessage now points to the struct AMessage variable posted + // by vATask. + } + } + + // ... Rest of task code. + } + </pre> + * \defgroup xQueueReceive xQueueReceive + * \ingroup QueueManagement + */ +#define xQueueReceive( xQueue, pvBuffer, xTicksToWait ) xQueueGenericReceive( ( xQueue ), ( pvBuffer ), ( xTicksToWait ), pdFALSE ) + + +/** + * queue. h + * <pre> + BaseType_t xQueueGenericReceive( + QueueHandle_t xQueue, + void *pvBuffer, + TickType_t xTicksToWait + BaseType_t xJustPeek + );</pre> + * + * It is preferred that the macro xQueueReceive() be used rather than calling + * this function directly. + * + * Receive an item from a queue. The item is received by copy so a buffer of + * adequate size must be provided. The number of bytes copied into the buffer + * was defined when the queue was created. + * + * This function must not be used in an interrupt service routine. See + * xQueueReceiveFromISR for an alternative that can. + * + * @param xQueue The handle to the queue from which the item is to be + * received. + * + * @param pvBuffer Pointer to the buffer into which the received item will + * be copied. + * + * @param xTicksToWait The maximum amount of time the task should block + * waiting for an item to receive should the queue be empty at the time + * of the call. The time is defined in tick periods so the constant + * portTICK_PERIOD_MS should be used to convert to real time if this is required. + * xQueueGenericReceive() will return immediately if the queue is empty and + * xTicksToWait is 0. + * + * @param xJustPeek When set to true, the item received from the queue is not + * actually removed from the queue - meaning a subsequent call to + * xQueueReceive() will return the same item. When set to false, the item + * being received from the queue is also removed from the queue. + * + * @return pdTRUE if an item was successfully received from the queue, + * otherwise pdFALSE. + * + * Example usage: + <pre> + struct AMessage + { + char ucMessageID; + char ucData[ 20 ]; + } xMessage; + + QueueHandle_t xQueue; + + // Task to create a queue and post a value. + void vATask( void *pvParameters ) + { + struct AMessage *pxMessage; + + // Create a queue capable of containing 10 pointers to AMessage structures. + // These should be passed by pointer as they contain a lot of data. + xQueue = xQueueCreate( 10, sizeof( struct AMessage * ) ); + if( xQueue == 0 ) + { + // Failed to create the queue. + } + + // ... + + // Send a pointer to a struct AMessage object. Don't block if the + // queue is already full. + pxMessage = & xMessage; + xQueueSend( xQueue, ( void * ) &pxMessage, ( TickType_t ) 0 ); + + // ... Rest of task code. + } + + // Task to receive from the queue. + void vADifferentTask( void *pvParameters ) + { + struct AMessage *pxRxedMessage; + + if( xQueue != 0 ) + { + // Receive a message on the created queue. Block for 10 ticks if a + // message is not immediately available. + if( xQueueGenericReceive( xQueue, &( pxRxedMessage ), ( TickType_t ) 10 ) ) + { + // pcRxedMessage now points to the struct AMessage variable posted + // by vATask. + } + } + + // ... Rest of task code. + } + </pre> + * \defgroup xQueueReceive xQueueReceive + * \ingroup QueueManagement + */ +BaseType_t xQueueGenericReceive( QueueHandle_t xQueue, void * const pvBuffer, TickType_t xTicksToWait, const BaseType_t xJustPeek ) PRIVILEGED_FUNCTION; + +/** + * queue. h + * <pre>UBaseType_t uxQueueMessagesWaiting( const QueueHandle_t xQueue );</pre> + * + * Return the number of messages stored in a queue. + * + * @param xQueue A handle to the queue being queried. + * + * @return The number of messages available in the queue. + * + * \defgroup uxQueueMessagesWaiting uxQueueMessagesWaiting + * \ingroup QueueManagement + */ +UBaseType_t uxQueueMessagesWaiting( const QueueHandle_t xQueue ) PRIVILEGED_FUNCTION; + +/** + * queue. h + * <pre>UBaseType_t uxQueueSpacesAvailable( const QueueHandle_t xQueue );</pre> + * + * Return the number of free spaces available in a queue. This is equal to the + * number of items that can be sent to the queue before the queue becomes full + * if no items are removed. + * + * @param xQueue A handle to the queue being queried. + * + * @return The number of spaces available in the queue. + * + * \defgroup uxQueueMessagesWaiting uxQueueMessagesWaiting + * \ingroup QueueManagement + */ +UBaseType_t uxQueueSpacesAvailable( const QueueHandle_t xQueue ) PRIVILEGED_FUNCTION; + +/** + * queue. h + * <pre>void vQueueDelete( QueueHandle_t xQueue );</pre> + * + * Delete a queue - freeing all the memory allocated for storing of items + * placed on the queue. + * + * @param xQueue A handle to the queue to be deleted. + * + * \defgroup vQueueDelete vQueueDelete + * \ingroup QueueManagement + */ +void vQueueDelete( QueueHandle_t xQueue ) PRIVILEGED_FUNCTION; + +/** + * queue. h + * <pre> + BaseType_t xQueueSendToFrontFromISR( + QueueHandle_t xQueue, + const void *pvItemToQueue, + BaseType_t *pxHigherPriorityTaskWoken + ); + </pre> + * + * This is a macro that calls xQueueGenericSendFromISR(). + * + * Post an item to the front of a queue. It is safe to use this macro from + * within an interrupt service routine. + * + * Items are queued by copy not reference so it is preferable to only + * queue small items, especially when called from an ISR. In most cases + * it would be preferable to store a pointer to the item being queued. + * + * @param xQueue The handle to the queue on which the item is to be posted. + * + * @param pvItemToQueue A pointer to the item that is to be placed on the + * queue. The size of the items the queue will hold was defined when the + * queue was created, so this many bytes will be copied from pvItemToQueue + * into the queue storage area. + * + * @param pxHigherPriorityTaskWoken xQueueSendToFrontFromISR() will set + * *pxHigherPriorityTaskWoken to pdTRUE if sending to the queue caused a task + * to unblock, and the unblocked task has a priority higher than the currently + * running task. If xQueueSendToFromFromISR() sets this value to pdTRUE then + * a context switch should be requested before the interrupt is exited. + * + * @return pdTRUE if the data was successfully sent to the queue, otherwise + * errQUEUE_FULL. + * + * Example usage for buffered IO (where the ISR can obtain more than one value + * per call): + <pre> + void vBufferISR( void ) + { + char cIn; + BaseType_t xHigherPrioritTaskWoken; + + // We have not woken a task at the start of the ISR. + xHigherPriorityTaskWoken = pdFALSE; + + // Loop until the buffer is empty. + do + { + // Obtain a byte from the buffer. + cIn = portINPUT_BYTE( RX_REGISTER_ADDRESS ); + + // Post the byte. + xQueueSendToFrontFromISR( xRxQueue, &cIn, &xHigherPriorityTaskWoken ); + + } while( portINPUT_BYTE( BUFFER_COUNT ) ); + + // Now the buffer is empty we can switch context if necessary. + if( xHigherPriorityTaskWoken ) + { + taskYIELD (); + } + } + </pre> + * + * \defgroup xQueueSendFromISR xQueueSendFromISR + * \ingroup QueueManagement + */ +#define xQueueSendToFrontFromISR( xQueue, pvItemToQueue, pxHigherPriorityTaskWoken ) xQueueGenericSendFromISR( ( xQueue ), ( pvItemToQueue ), ( pxHigherPriorityTaskWoken ), queueSEND_TO_FRONT ) + + +/** + * queue. h + * <pre> + BaseType_t xQueueSendToBackFromISR( + QueueHandle_t xQueue, + const void *pvItemToQueue, + BaseType_t *pxHigherPriorityTaskWoken + ); + </pre> + * + * This is a macro that calls xQueueGenericSendFromISR(). + * + * Post an item to the back of a queue. It is safe to use this macro from + * within an interrupt service routine. + * + * Items are queued by copy not reference so it is preferable to only + * queue small items, especially when called from an ISR. In most cases + * it would be preferable to store a pointer to the item being queued. + * + * @param xQueue The handle to the queue on which the item is to be posted. + * + * @param pvItemToQueue A pointer to the item that is to be placed on the + * queue. The size of the items the queue will hold was defined when the + * queue was created, so this many bytes will be copied from pvItemToQueue + * into the queue storage area. + * + * @param pxHigherPriorityTaskWoken xQueueSendToBackFromISR() will set + * *pxHigherPriorityTaskWoken to pdTRUE if sending to the queue caused a task + * to unblock, and the unblocked task has a priority higher than the currently + * running task. If xQueueSendToBackFromISR() sets this value to pdTRUE then + * a context switch should be requested before the interrupt is exited. + * + * @return pdTRUE if the data was successfully sent to the queue, otherwise + * errQUEUE_FULL. + * + * Example usage for buffered IO (where the ISR can obtain more than one value + * per call): + <pre> + void vBufferISR( void ) + { + char cIn; + BaseType_t xHigherPriorityTaskWoken; + + // We have not woken a task at the start of the ISR. + xHigherPriorityTaskWoken = pdFALSE; + + // Loop until the buffer is empty. + do + { + // Obtain a byte from the buffer. + cIn = portINPUT_BYTE( RX_REGISTER_ADDRESS ); + + // Post the byte. + xQueueSendToBackFromISR( xRxQueue, &cIn, &xHigherPriorityTaskWoken ); + + } while( portINPUT_BYTE( BUFFER_COUNT ) ); + + // Now the buffer is empty we can switch context if necessary. + if( xHigherPriorityTaskWoken ) + { + taskYIELD (); + } + } + </pre> + * + * \defgroup xQueueSendFromISR xQueueSendFromISR + * \ingroup QueueManagement + */ +#define xQueueSendToBackFromISR( xQueue, pvItemToQueue, pxHigherPriorityTaskWoken ) xQueueGenericSendFromISR( ( xQueue ), ( pvItemToQueue ), ( pxHigherPriorityTaskWoken ), queueSEND_TO_BACK ) + +/** + * queue. h + * <pre> + BaseType_t xQueueOverwriteFromISR( + QueueHandle_t xQueue, + const void * pvItemToQueue, + BaseType_t *pxHigherPriorityTaskWoken + ); + * </pre> + * + * A version of xQueueOverwrite() that can be used in an interrupt service + * routine (ISR). + * + * Only for use with queues that can hold a single item - so the queue is either + * empty or full. + * + * Post an item on a queue. If the queue is already full then overwrite the + * value held in the queue. The item is queued by copy, not by reference. + * + * @param xQueue The handle to the queue on which the item is to be posted. + * + * @param pvItemToQueue A pointer to the item that is to be placed on the + * queue. The size of the items the queue will hold was defined when the + * queue was created, so this many bytes will be copied from pvItemToQueue + * into the queue storage area. + * + * @param pxHigherPriorityTaskWoken xQueueOverwriteFromISR() will set + * *pxHigherPriorityTaskWoken to pdTRUE if sending to the queue caused a task + * to unblock, and the unblocked task has a priority higher than the currently + * running task. If xQueueOverwriteFromISR() sets this value to pdTRUE then + * a context switch should be requested before the interrupt is exited. + * + * @return xQueueOverwriteFromISR() is a macro that calls + * xQueueGenericSendFromISR(), and therefore has the same return values as + * xQueueSendToFrontFromISR(). However, pdPASS is the only value that can be + * returned because xQueueOverwriteFromISR() will write to the queue even when + * the queue is already full. + * + * Example usage: + <pre> + + QueueHandle_t xQueue; + + void vFunction( void *pvParameters ) + { + // Create a queue to hold one uint32_t value. It is strongly + // recommended *not* to use xQueueOverwriteFromISR() on queues that can + // contain more than one value, and doing so will trigger an assertion + // if configASSERT() is defined. + xQueue = xQueueCreate( 1, sizeof( uint32_t ) ); +} + +void vAnInterruptHandler( void ) +{ +// xHigherPriorityTaskWoken must be set to pdFALSE before it is used. +BaseType_t xHigherPriorityTaskWoken = pdFALSE; +uint32_t ulVarToSend, ulValReceived; + + // Write the value 10 to the queue using xQueueOverwriteFromISR(). + ulVarToSend = 10; + xQueueOverwriteFromISR( xQueue, &ulVarToSend, &xHigherPriorityTaskWoken ); + + // The queue is full, but calling xQueueOverwriteFromISR() again will still + // pass because the value held in the queue will be overwritten with the + // new value. + ulVarToSend = 100; + xQueueOverwriteFromISR( xQueue, &ulVarToSend, &xHigherPriorityTaskWoken ); + + // Reading from the queue will now return 100. + + // ... + + if( xHigherPrioritytaskWoken == pdTRUE ) + { + // Writing to the queue caused a task to unblock and the unblocked task + // has a priority higher than or equal to the priority of the currently + // executing task (the task this interrupt interrupted). Perform a context + // switch so this interrupt returns directly to the unblocked task. + portYIELD_FROM_ISR(); // or portEND_SWITCHING_ISR() depending on the port. + } +} + </pre> + * \defgroup xQueueOverwriteFromISR xQueueOverwriteFromISR + * \ingroup QueueManagement + */ +#define xQueueOverwriteFromISR( xQueue, pvItemToQueue, pxHigherPriorityTaskWoken ) xQueueGenericSendFromISR( ( xQueue ), ( pvItemToQueue ), ( pxHigherPriorityTaskWoken ), queueOVERWRITE ) + +/** + * queue. h + * <pre> + BaseType_t xQueueSendFromISR( + QueueHandle_t xQueue, + const void *pvItemToQueue, + BaseType_t *pxHigherPriorityTaskWoken + ); + </pre> + * + * This is a macro that calls xQueueGenericSendFromISR(). It is included + * for backward compatibility with versions of FreeRTOS.org that did not + * include the xQueueSendToBackFromISR() and xQueueSendToFrontFromISR() + * macros. + * + * Post an item to the back of a queue. It is safe to use this function from + * within an interrupt service routine. + * + * Items are queued by copy not reference so it is preferable to only + * queue small items, especially when called from an ISR. In most cases + * it would be preferable to store a pointer to the item being queued. + * + * @param xQueue The handle to the queue on which the item is to be posted. + * + * @param pvItemToQueue A pointer to the item that is to be placed on the + * queue. The size of the items the queue will hold was defined when the + * queue was created, so this many bytes will be copied from pvItemToQueue + * into the queue storage area. + * + * @param pxHigherPriorityTaskWoken xQueueSendFromISR() will set + * *pxHigherPriorityTaskWoken to pdTRUE if sending to the queue caused a task + * to unblock, and the unblocked task has a priority higher than the currently + * running task. If xQueueSendFromISR() sets this value to pdTRUE then + * a context switch should be requested before the interrupt is exited. + * + * @return pdTRUE if the data was successfully sent to the queue, otherwise + * errQUEUE_FULL. + * + * Example usage for buffered IO (where the ISR can obtain more than one value + * per call): + <pre> + void vBufferISR( void ) + { + char cIn; + BaseType_t xHigherPriorityTaskWoken; + + // We have not woken a task at the start of the ISR. + xHigherPriorityTaskWoken = pdFALSE; + + // Loop until the buffer is empty. + do + { + // Obtain a byte from the buffer. + cIn = portINPUT_BYTE( RX_REGISTER_ADDRESS ); + + // Post the byte. + xQueueSendFromISR( xRxQueue, &cIn, &xHigherPriorityTaskWoken ); + + } while( portINPUT_BYTE( BUFFER_COUNT ) ); + + // Now the buffer is empty we can switch context if necessary. + if( xHigherPriorityTaskWoken ) + { + // Actual macro used here is port specific. + portYIELD_FROM_ISR (); + } + } + </pre> + * + * \defgroup xQueueSendFromISR xQueueSendFromISR + * \ingroup QueueManagement + */ +#define xQueueSendFromISR( xQueue, pvItemToQueue, pxHigherPriorityTaskWoken ) xQueueGenericSendFromISR( ( xQueue ), ( pvItemToQueue ), ( pxHigherPriorityTaskWoken ), queueSEND_TO_BACK ) + +/** + * queue. h + * <pre> + BaseType_t xQueueGenericSendFromISR( + QueueHandle_t xQueue, + const void *pvItemToQueue, + BaseType_t *pxHigherPriorityTaskWoken, + BaseType_t xCopyPosition + ); + </pre> + * + * It is preferred that the macros xQueueSendFromISR(), + * xQueueSendToFrontFromISR() and xQueueSendToBackFromISR() be used in place + * of calling this function directly. xQueueGiveFromISR() is an + * equivalent for use by semaphores that don't actually copy any data. + * + * Post an item on a queue. It is safe to use this function from within an + * interrupt service routine. + * + * Items are queued by copy not reference so it is preferable to only + * queue small items, especially when called from an ISR. In most cases + * it would be preferable to store a pointer to the item being queued. + * + * @param xQueue The handle to the queue on which the item is to be posted. + * + * @param pvItemToQueue A pointer to the item that is to be placed on the + * queue. The size of the items the queue will hold was defined when the + * queue was created, so this many bytes will be copied from pvItemToQueue + * into the queue storage area. + * + * @param pxHigherPriorityTaskWoken xQueueGenericSendFromISR() will set + * *pxHigherPriorityTaskWoken to pdTRUE if sending to the queue caused a task + * to unblock, and the unblocked task has a priority higher than the currently + * running task. If xQueueGenericSendFromISR() sets this value to pdTRUE then + * a context switch should be requested before the interrupt is exited. + * + * @param xCopyPosition Can take the value queueSEND_TO_BACK to place the + * item at the back of the queue, or queueSEND_TO_FRONT to place the item + * at the front of the queue (for high priority messages). + * + * @return pdTRUE if the data was successfully sent to the queue, otherwise + * errQUEUE_FULL. + * + * Example usage for buffered IO (where the ISR can obtain more than one value + * per call): + <pre> + void vBufferISR( void ) + { + char cIn; + BaseType_t xHigherPriorityTaskWokenByPost; + + // We have not woken a task at the start of the ISR. + xHigherPriorityTaskWokenByPost = pdFALSE; + + // Loop until the buffer is empty. + do + { + // Obtain a byte from the buffer. + cIn = portINPUT_BYTE( RX_REGISTER_ADDRESS ); + + // Post each byte. + xQueueGenericSendFromISR( xRxQueue, &cIn, &xHigherPriorityTaskWokenByPost, queueSEND_TO_BACK ); + + } while( portINPUT_BYTE( BUFFER_COUNT ) ); + + // Now the buffer is empty we can switch context if necessary. Note that the + // name of the yield function required is port specific. + if( xHigherPriorityTaskWokenByPost ) + { + taskYIELD_YIELD_FROM_ISR(); + } + } + </pre> + * + * \defgroup xQueueSendFromISR xQueueSendFromISR + * \ingroup QueueManagement + */ +BaseType_t xQueueGenericSendFromISR( QueueHandle_t xQueue, const void * const pvItemToQueue, BaseType_t * const pxHigherPriorityTaskWoken, const BaseType_t xCopyPosition ) PRIVILEGED_FUNCTION; +BaseType_t xQueueGiveFromISR( QueueHandle_t xQueue, BaseType_t * const pxHigherPriorityTaskWoken ) PRIVILEGED_FUNCTION; + +/** + * queue. h + * <pre> + BaseType_t xQueueReceiveFromISR( + QueueHandle_t xQueue, + void *pvBuffer, + BaseType_t *pxTaskWoken + ); + * </pre> + * + * Receive an item from a queue. It is safe to use this function from within an + * interrupt service routine. + * + * @param xQueue The handle to the queue from which the item is to be + * received. + * + * @param pvBuffer Pointer to the buffer into which the received item will + * be copied. + * + * @param pxTaskWoken A task may be blocked waiting for space to become + * available on the queue. If xQueueReceiveFromISR causes such a task to + * unblock *pxTaskWoken will get set to pdTRUE, otherwise *pxTaskWoken will + * remain unchanged. + * + * @return pdTRUE if an item was successfully received from the queue, + * otherwise pdFALSE. + * + * Example usage: + <pre> + + QueueHandle_t xQueue; + + // Function to create a queue and post some values. + void vAFunction( void *pvParameters ) + { + char cValueToPost; + const TickType_t xTicksToWait = ( TickType_t )0xff; + + // Create a queue capable of containing 10 characters. + xQueue = xQueueCreate( 10, sizeof( char ) ); + if( xQueue == 0 ) + { + // Failed to create the queue. + } + + // ... + + // Post some characters that will be used within an ISR. If the queue + // is full then this task will block for xTicksToWait ticks. + cValueToPost = 'a'; + xQueueSend( xQueue, ( void * ) &cValueToPost, xTicksToWait ); + cValueToPost = 'b'; + xQueueSend( xQueue, ( void * ) &cValueToPost, xTicksToWait ); + + // ... keep posting characters ... this task may block when the queue + // becomes full. + + cValueToPost = 'c'; + xQueueSend( xQueue, ( void * ) &cValueToPost, xTicksToWait ); + } + + // ISR that outputs all the characters received on the queue. + void vISR_Routine( void ) + { + BaseType_t xTaskWokenByReceive = pdFALSE; + char cRxedChar; + + while( xQueueReceiveFromISR( xQueue, ( void * ) &cRxedChar, &xTaskWokenByReceive) ) + { + // A character was received. Output the character now. + vOutputCharacter( cRxedChar ); + + // If removing the character from the queue woke the task that was + // posting onto the queue cTaskWokenByReceive will have been set to + // pdTRUE. No matter how many times this loop iterates only one + // task will be woken. + } + + if( cTaskWokenByPost != ( char ) pdFALSE; + { + taskYIELD (); + } + } + </pre> + * \defgroup xQueueReceiveFromISR xQueueReceiveFromISR + * \ingroup QueueManagement + */ +BaseType_t xQueueReceiveFromISR( QueueHandle_t xQueue, void * const pvBuffer, BaseType_t * const pxHigherPriorityTaskWoken ) PRIVILEGED_FUNCTION; + +/* + * Utilities to query queues that are safe to use from an ISR. These utilities + * should be used only from witin an ISR, or within a critical section. + */ +BaseType_t xQueueIsQueueEmptyFromISR( const QueueHandle_t xQueue ) PRIVILEGED_FUNCTION; +BaseType_t xQueueIsQueueFullFromISR( const QueueHandle_t xQueue ) PRIVILEGED_FUNCTION; +UBaseType_t uxQueueMessagesWaitingFromISR( const QueueHandle_t xQueue ) PRIVILEGED_FUNCTION; + +/* + * The functions defined above are for passing data to and from tasks. The + * functions below are the equivalents for passing data to and from + * co-routines. + * + * These functions are called from the co-routine macro implementation and + * should not be called directly from application code. Instead use the macro + * wrappers defined within croutine.h. + */ +BaseType_t xQueueCRSendFromISR( QueueHandle_t xQueue, const void *pvItemToQueue, BaseType_t xCoRoutinePreviouslyWoken ); +BaseType_t xQueueCRReceiveFromISR( QueueHandle_t xQueue, void *pvBuffer, BaseType_t *pxTaskWoken ); +BaseType_t xQueueCRSend( QueueHandle_t xQueue, const void *pvItemToQueue, TickType_t xTicksToWait ); +BaseType_t xQueueCRReceive( QueueHandle_t xQueue, void *pvBuffer, TickType_t xTicksToWait ); + +/* + * For internal use only. Use xSemaphoreCreateMutex(), + * xSemaphoreCreateCounting() or xSemaphoreGetMutexHolder() instead of calling + * these functions directly. + */ +QueueHandle_t xQueueCreateMutex( const uint8_t ucQueueType ) PRIVILEGED_FUNCTION; +QueueHandle_t xQueueCreateMutexStatic( const uint8_t ucQueueType, StaticQueue_t *pxStaticQueue ) PRIVILEGED_FUNCTION; +QueueHandle_t xQueueCreateCountingSemaphore( const UBaseType_t uxMaxCount, const UBaseType_t uxInitialCount ) PRIVILEGED_FUNCTION; +QueueHandle_t xQueueCreateCountingSemaphoreStatic( const UBaseType_t uxMaxCount, const UBaseType_t uxInitialCount, StaticQueue_t *pxStaticQueue ) PRIVILEGED_FUNCTION; +void* xQueueGetMutexHolder( QueueHandle_t xSemaphore ) PRIVILEGED_FUNCTION; + +/* + * For internal use only. Use xSemaphoreTakeMutexRecursive() or + * xSemaphoreGiveMutexRecursive() instead of calling these functions directly. + */ +BaseType_t xQueueTakeMutexRecursive( QueueHandle_t xMutex, TickType_t xTicksToWait ) PRIVILEGED_FUNCTION; +BaseType_t xQueueGiveMutexRecursive( QueueHandle_t pxMutex ) PRIVILEGED_FUNCTION; + +/* + * Reset a queue back to its original empty state. The return value is now + * obsolete and is always set to pdPASS. + */ +#define xQueueReset( xQueue ) xQueueGenericReset( xQueue, pdFALSE ) + +/* + * The registry is provided as a means for kernel aware debuggers to + * locate queues, semaphores and mutexes. Call vQueueAddToRegistry() add + * a queue, semaphore or mutex handle to the registry if you want the handle + * to be available to a kernel aware debugger. If you are not using a kernel + * aware debugger then this function can be ignored. + * + * configQUEUE_REGISTRY_SIZE defines the maximum number of handles the + * registry can hold. configQUEUE_REGISTRY_SIZE must be greater than 0 + * within FreeRTOSConfig.h for the registry to be available. Its value + * does not effect the number of queues, semaphores and mutexes that can be + * created - just the number that the registry can hold. + * + * @param xQueue The handle of the queue being added to the registry. This + * is the handle returned by a call to xQueueCreate(). Semaphore and mutex + * handles can also be passed in here. + * + * @param pcName The name to be associated with the handle. This is the + * name that the kernel aware debugger will display. The queue registry only + * stores a pointer to the string - so the string must be persistent (global or + * preferably in ROM/Flash), not on the stack. + */ +#if( configQUEUE_REGISTRY_SIZE > 0 ) + void vQueueAddToRegistry( QueueHandle_t xQueue, const char *pcName ) PRIVILEGED_FUNCTION; /*lint !e971 Unqualified char types are allowed for strings and single characters only. */ +#endif + +/* + * The registry is provided as a means for kernel aware debuggers to + * locate queues, semaphores and mutexes. Call vQueueAddToRegistry() add + * a queue, semaphore or mutex handle to the registry if you want the handle + * to be available to a kernel aware debugger, and vQueueUnregisterQueue() to + * remove the queue, semaphore or mutex from the register. If you are not using + * a kernel aware debugger then this function can be ignored. + * + * @param xQueue The handle of the queue being removed from the registry. + */ +#if( configQUEUE_REGISTRY_SIZE > 0 ) + void vQueueUnregisterQueue( QueueHandle_t xQueue ) PRIVILEGED_FUNCTION; +#endif + +/* + * The queue registry is provided as a means for kernel aware debuggers to + * locate queues, semaphores and mutexes. Call pcQueueGetName() to look + * up and return the name of a queue in the queue registry from the queue's + * handle. + * + * @param xQueue The handle of the queue the name of which will be returned. + * @return If the queue is in the registry then a pointer to the name of the + * queue is returned. If the queue is not in the registry then NULL is + * returned. + */ +#if( configQUEUE_REGISTRY_SIZE > 0 ) + const char *pcQueueGetName( QueueHandle_t xQueue ) PRIVILEGED_FUNCTION; /*lint !e971 Unqualified char types are allowed for strings and single characters only. */ +#endif + +/* + * Generic version of the function used to creaet a queue using dynamic memory + * allocation. This is called by other functions and macros that create other + * RTOS objects that use the queue structure as their base. + */ +#if( configSUPPORT_DYNAMIC_ALLOCATION == 1 ) + QueueHandle_t xQueueGenericCreate( const UBaseType_t uxQueueLength, const UBaseType_t uxItemSize, const uint8_t ucQueueType ) PRIVILEGED_FUNCTION; +#endif + +/* + * Generic version of the function used to creaet a queue using dynamic memory + * allocation. This is called by other functions and macros that create other + * RTOS objects that use the queue structure as their base. + */ +#if( configSUPPORT_STATIC_ALLOCATION == 1 ) + QueueHandle_t xQueueGenericCreateStatic( const UBaseType_t uxQueueLength, const UBaseType_t uxItemSize, uint8_t *pucQueueStorage, StaticQueue_t *pxStaticQueue, const uint8_t ucQueueType ) PRIVILEGED_FUNCTION; +#endif + +/* + * Queue sets provide a mechanism to allow a task to block (pend) on a read + * operation from multiple queues or semaphores simultaneously. + * + * See FreeRTOS/Source/Demo/Common/Minimal/QueueSet.c for an example using this + * function. + * + * A queue set must be explicitly created using a call to xQueueCreateSet() + * before it can be used. Once created, standard FreeRTOS queues and semaphores + * can be added to the set using calls to xQueueAddToSet(). + * xQueueSelectFromSet() is then used to determine which, if any, of the queues + * or semaphores contained in the set is in a state where a queue read or + * semaphore take operation would be successful. + * + * Note 1: See the documentation on http://wwwFreeRTOS.org/RTOS-queue-sets.html + * for reasons why queue sets are very rarely needed in practice as there are + * simpler methods of blocking on multiple objects. + * + * Note 2: Blocking on a queue set that contains a mutex will not cause the + * mutex holder to inherit the priority of the blocked task. + * + * Note 3: An additional 4 bytes of RAM is required for each space in a every + * queue added to a queue set. Therefore counting semaphores that have a high + * maximum count value should not be added to a queue set. + * + * Note 4: A receive (in the case of a queue) or take (in the case of a + * semaphore) operation must not be performed on a member of a queue set unless + * a call to xQueueSelectFromSet() has first returned a handle to that set member. + * + * @param uxEventQueueLength Queue sets store events that occur on + * the queues and semaphores contained in the set. uxEventQueueLength specifies + * the maximum number of events that can be queued at once. To be absolutely + * certain that events are not lost uxEventQueueLength should be set to the + * total sum of the length of the queues added to the set, where binary + * semaphores and mutexes have a length of 1, and counting semaphores have a + * length set by their maximum count value. Examples: + * + If a queue set is to hold a queue of length 5, another queue of length 12, + * and a binary semaphore, then uxEventQueueLength should be set to + * (5 + 12 + 1), or 18. + * + If a queue set is to hold three binary semaphores then uxEventQueueLength + * should be set to (1 + 1 + 1 ), or 3. + * + If a queue set is to hold a counting semaphore that has a maximum count of + * 5, and a counting semaphore that has a maximum count of 3, then + * uxEventQueueLength should be set to (5 + 3), or 8. + * + * @return If the queue set is created successfully then a handle to the created + * queue set is returned. Otherwise NULL is returned. + */ +QueueSetHandle_t xQueueCreateSet( const UBaseType_t uxEventQueueLength ) PRIVILEGED_FUNCTION; + +/* + * Adds a queue or semaphore to a queue set that was previously created by a + * call to xQueueCreateSet(). + * + * See FreeRTOS/Source/Demo/Common/Minimal/QueueSet.c for an example using this + * function. + * + * Note 1: A receive (in the case of a queue) or take (in the case of a + * semaphore) operation must not be performed on a member of a queue set unless + * a call to xQueueSelectFromSet() has first returned a handle to that set member. + * + * @param xQueueOrSemaphore The handle of the queue or semaphore being added to + * the queue set (cast to an QueueSetMemberHandle_t type). + * + * @param xQueueSet The handle of the queue set to which the queue or semaphore + * is being added. + * + * @return If the queue or semaphore was successfully added to the queue set + * then pdPASS is returned. If the queue could not be successfully added to the + * queue set because it is already a member of a different queue set then pdFAIL + * is returned. + */ +BaseType_t xQueueAddToSet( QueueSetMemberHandle_t xQueueOrSemaphore, QueueSetHandle_t xQueueSet ) PRIVILEGED_FUNCTION; + +/* + * Removes a queue or semaphore from a queue set. A queue or semaphore can only + * be removed from a set if the queue or semaphore is empty. + * + * See FreeRTOS/Source/Demo/Common/Minimal/QueueSet.c for an example using this + * function. + * + * @param xQueueOrSemaphore The handle of the queue or semaphore being removed + * from the queue set (cast to an QueueSetMemberHandle_t type). + * + * @param xQueueSet The handle of the queue set in which the queue or semaphore + * is included. + * + * @return If the queue or semaphore was successfully removed from the queue set + * then pdPASS is returned. If the queue was not in the queue set, or the + * queue (or semaphore) was not empty, then pdFAIL is returned. + */ +BaseType_t xQueueRemoveFromSet( QueueSetMemberHandle_t xQueueOrSemaphore, QueueSetHandle_t xQueueSet ) PRIVILEGED_FUNCTION; + +/* + * xQueueSelectFromSet() selects from the members of a queue set a queue or + * semaphore that either contains data (in the case of a queue) or is available + * to take (in the case of a semaphore). xQueueSelectFromSet() effectively + * allows a task to block (pend) on a read operation on all the queues and + * semaphores in a queue set simultaneously. + * + * See FreeRTOS/Source/Demo/Common/Minimal/QueueSet.c for an example using this + * function. + * + * Note 1: See the documentation on http://wwwFreeRTOS.org/RTOS-queue-sets.html + * for reasons why queue sets are very rarely needed in practice as there are + * simpler methods of blocking on multiple objects. + * + * Note 2: Blocking on a queue set that contains a mutex will not cause the + * mutex holder to inherit the priority of the blocked task. + * + * Note 3: A receive (in the case of a queue) or take (in the case of a + * semaphore) operation must not be performed on a member of a queue set unless + * a call to xQueueSelectFromSet() has first returned a handle to that set member. + * + * @param xQueueSet The queue set on which the task will (potentially) block. + * + * @param xTicksToWait The maximum time, in ticks, that the calling task will + * remain in the Blocked state (with other tasks executing) to wait for a member + * of the queue set to be ready for a successful queue read or semaphore take + * operation. + * + * @return xQueueSelectFromSet() will return the handle of a queue (cast to + * a QueueSetMemberHandle_t type) contained in the queue set that contains data, + * or the handle of a semaphore (cast to a QueueSetMemberHandle_t type) contained + * in the queue set that is available, or NULL if no such queue or semaphore + * exists before before the specified block time expires. + */ +QueueSetMemberHandle_t xQueueSelectFromSet( QueueSetHandle_t xQueueSet, const TickType_t xTicksToWait ) PRIVILEGED_FUNCTION; + +/* + * A version of xQueueSelectFromSet() that can be used from an ISR. + */ +QueueSetMemberHandle_t xQueueSelectFromSetFromISR( QueueSetHandle_t xQueueSet ) PRIVILEGED_FUNCTION; + +/* Not public API functions. */ +void vQueueWaitForMessageRestricted( QueueHandle_t xQueue, TickType_t xTicksToWait, const BaseType_t xWaitIndefinitely ) PRIVILEGED_FUNCTION; +BaseType_t xQueueGenericReset( QueueHandle_t xQueue, BaseType_t xNewQueue ) PRIVILEGED_FUNCTION; +void vQueueSetQueueNumber( QueueHandle_t xQueue, UBaseType_t uxQueueNumber ) PRIVILEGED_FUNCTION; +UBaseType_t uxQueueGetQueueNumber( QueueHandle_t xQueue ) PRIVILEGED_FUNCTION; +uint8_t ucQueueGetQueueType( QueueHandle_t xQueue ) PRIVILEGED_FUNCTION; + + +#ifdef __cplusplus +} +#endif + +#endif /* QUEUE_H */ + |