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Source/include/queue.h
- Committer:
- ser1516
- Date:
- 2016-05-18
- Revision:
- 1:6db425da9b9e
- Parent:
- 0:8e57f3e9cc89
File content as of revision 1:6db425da9b9e:
/* FreeRTOS V7.6.0 - Copyright (C) 2013 Real Time Engineers Ltd. All rights reserved VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION. *************************************************************************** * * * FreeRTOS provides completely free yet professionally developed, * * robust, strictly quality controlled, supported, and cross * * platform software that has become a de facto standard. * * * * Help yourself get started quickly and support the FreeRTOS * * project by purchasing a FreeRTOS tutorial book, reference * * manual, or both from: http://www.FreeRTOS.org/Documentation * * * * Thank you! * * * *************************************************************************** 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 from the following link: http://www.freertos.org/a00114.html 1 tab == 4 spaces! *************************************************************************** * * * Having a problem? Start by reading the FAQ "My application does * * not run, what could be wrong?" * * * * http://www.FreeRTOS.org/FAQHelp.html * * * *************************************************************************** http://www.FreeRTOS.org - Documentation, books, training, latest versions, license and Real Time Engineers Ltd. contact details. 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.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High Integrity Systems to sell under the OpenRTOS brand. Low cost OpenRTOS licenses offer ticketed support, indemnification and 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 xQueueHandle variable that can then be used as a parameter to * xQueueSend(), xQueueReceive(), etc. */ typedef void * xQueueHandle; /** * 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 * xQueueSetHandle; /** * Queue sets can contain both queues and semaphores, so the * xQueueSetMemberHandle is defined as a type to be used where a parameter or * return value can be either an xQueueHandle or an xSemaphoreHandle. */ typedef void * xQueueSetMemberHandle; /* For internal use only. */ #define queueSEND_TO_BACK ( ( portBASE_TYPE ) 0 ) #define queueSEND_TO_FRONT ( ( portBASE_TYPE ) 1 ) #define queueOVERWRITE ( ( portBASE_TYPE ) 2 ) /* For internal use only. These definitions *must* match those in queue.c. */ #define queueQUEUE_TYPE_BASE ( ( unsigned char ) 0U ) #define queueQUEUE_TYPE_SET ( ( unsigned char ) 0U ) #define queueQUEUE_TYPE_MUTEX ( ( unsigned char ) 1U ) #define queueQUEUE_TYPE_COUNTING_SEMAPHORE ( ( unsigned char ) 2U ) #define queueQUEUE_TYPE_BINARY_SEMAPHORE ( ( unsigned char ) 3U ) #define queueQUEUE_TYPE_RECURSIVE_MUTEX ( ( unsigned char ) 4U ) /** * queue. h * <pre> xQueueHandle xQueueCreate( unsigned portBASE_TYPE uxQueueLength, unsigned portBASE_TYPE uxItemSize ); * </pre> * * Creates a new queue instance. This allocates the storage required by the * new queue and returns a handle for the queue. * * @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 ) { xQueueHandle xQueue1, xQueue2; // Create a queue capable of containing 10 unsigned long values. xQueue1 = xQueueCreate( 10, sizeof( unsigned long ) ); 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 */ #define xQueueCreate( uxQueueLength, uxItemSize ) xQueueGenericCreate( uxQueueLength, uxItemSize, queueQUEUE_TYPE_BASE ) /** * queue. h * <pre> portBASE_TYPE xQueueSendToToFront( xQueueHandle xQueue, const void * pvItemToQueue, portTickType 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_RATE_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; unsigned long ulVar = 10UL; void vATask( void *pvParameters ) { xQueueHandle xQueue1, xQueue2; struct AMessage *pxMessage; // Create a queue capable of containing 10 unsigned long values. xQueue1 = xQueueCreate( 10, sizeof( unsigned long ) ); // 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 unsigned long. Wait for 10 ticks for space to become // available if necessary. if( xQueueSendToFront( xQueue1, ( void * ) &ulVar, ( portTickType ) 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, ( portTickType ) 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> portBASE_TYPE xQueueSendToBack( xQueueHandle xQueue, const void * pvItemToQueue, portTickType 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_RATE_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; unsigned long ulVar = 10UL; void vATask( void *pvParameters ) { xQueueHandle xQueue1, xQueue2; struct AMessage *pxMessage; // Create a queue capable of containing 10 unsigned long values. xQueue1 = xQueueCreate( 10, sizeof( unsigned long ) ); // 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 unsigned long. Wait for 10 ticks for space to become // available if necessary. if( xQueueSendToBack( xQueue1, ( void * ) &ulVar, ( portTickType ) 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, ( portTickType ) 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> portBASE_TYPE xQueueSend( xQueueHandle xQueue, const void * pvItemToQueue, portTickType 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_RATE_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; unsigned long ulVar = 10UL; void vATask( void *pvParameters ) { xQueueHandle xQueue1, xQueue2; struct AMessage *pxMessage; // Create a queue capable of containing 10 unsigned long values. xQueue1 = xQueueCreate( 10, sizeof( unsigned long ) ); // 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 unsigned long. Wait for 10 ticks for space to become // available if necessary. if( xQueueSend( xQueue1, ( void * ) &ulVar, ( portTickType ) 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, ( portTickType ) 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> portBASE_TYPE xQueueOverwrite( xQueueHandle 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 ) { xQueueHandle xQueue; unsigned long ulVarToSend, ulValReceived; // Create a queue to hold one unsigned long 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( unsigned long ) ); // 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> portBASE_TYPE xQueueGenericSend( xQueueHandle xQueue, const void * pvItemToQueue, portTickType xTicksToWait portBASE_TYPE 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_RATE_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; unsigned long ulVar = 10UL; void vATask( void *pvParameters ) { xQueueHandle xQueue1, xQueue2; struct AMessage *pxMessage; // Create a queue capable of containing 10 unsigned long values. xQueue1 = xQueueCreate( 10, sizeof( unsigned long ) ); // 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 unsigned long. Wait for 10 ticks for space to become // available if necessary. if( xQueueGenericSend( xQueue1, ( void * ) &ulVar, ( portTickType ) 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, ( portTickType ) 0, queueSEND_TO_BACK ); } // ... Rest of task code. } </pre> * \defgroup xQueueSend xQueueSend * \ingroup QueueManagement */ signed portBASE_TYPE xQueueGenericSend( xQueueHandle xQueue, const void * const pvItemToQueue, portTickType xTicksToWait, portBASE_TYPE xCopyPosition ) PRIVILEGED_FUNCTION; /** * queue. h * <pre> portBASE_TYPE xQueuePeek( xQueueHandle xQueue, void *pvBuffer, portTickType 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_RATE_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; xQueueHandle 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, ( portTickType ) 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 ), ( portTickType ) 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> portBASE_TYPE xQueuePeekFromISR( xQueueHandle 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 */ signed portBASE_TYPE xQueuePeekFromISR( xQueueHandle xQueue, void * const pvBuffer ) PRIVILEGED_FUNCTION; /** * queue. h * <pre> portBASE_TYPE xQueueReceive( xQueueHandle xQueue, void *pvBuffer, portTickType 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_RATE_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; xQueueHandle 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, ( portTickType ) 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 ), ( portTickType ) 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> portBASE_TYPE xQueueGenericReceive( xQueueHandle xQueue, void *pvBuffer, portTickType xTicksToWait portBASE_TYPE 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_RATE_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; xQueueHandle 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, ( portTickType ) 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 ), ( portTickType ) 10 ) ) { // pcRxedMessage now points to the struct AMessage variable posted // by vATask. } } // ... Rest of task code. } </pre> * \defgroup xQueueReceive xQueueReceive * \ingroup QueueManagement */ signed portBASE_TYPE xQueueGenericReceive( xQueueHandle xQueue, void * const pvBuffer, portTickType xTicksToWait, portBASE_TYPE xJustPeek ) PRIVILEGED_FUNCTION; /** * queue. h * <pre>unsigned portBASE_TYPE uxQueueMessagesWaiting( const xQueueHandle 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 */ unsigned portBASE_TYPE uxQueueMessagesWaiting( const xQueueHandle xQueue ) PRIVILEGED_FUNCTION; /** * queue. h * <pre>unsigned portBASE_TYPE uxQueueSpacesAvailable( const xQueueHandle 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 */ unsigned portBASE_TYPE uxQueueSpacesAvailable( const xQueueHandle xQueue ) PRIVILEGED_FUNCTION; /** * queue. h * <pre>void vQueueDelete( xQueueHandle 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( xQueueHandle xQueue ) PRIVILEGED_FUNCTION; /** * queue. h * <pre> portBASE_TYPE xQueueSendToFrontFromISR( xQueueHandle xQueue, const void *pvItemToQueue, portBASE_TYPE *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; portBASE_TYPE 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> portBASE_TYPE xQueueSendToBackFromISR( xQueueHandle xQueue, const void *pvItemToQueue, portBASE_TYPE *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; portBASE_TYPE 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> portBASE_TYPE xQueueOverwriteFromISR( xQueueHandle xQueue, const void * pvItemToQueue, portBASE_TYPE *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> xQueueHandle xQueue; void vFunction( void *pvParameters ) { // Create a queue to hold one unsigned long 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( unsigned long ) ); } void vAnInterruptHandler( void ) { // xHigherPriorityTaskWoken must be set to pdFALSE before it is used. portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE; unsigned long 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> portBASE_TYPE xQueueSendFromISR( xQueueHandle xQueue, const void *pvItemToQueue, portBASE_TYPE *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; portBASE_TYPE 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> portBASE_TYPE xQueueGenericSendFromISR( xQueueHandle xQueue, const void *pvItemToQueue, portBASE_TYPE *pxHigherPriorityTaskWoken, portBASE_TYPE xCopyPosition ); </pre> * * It is preferred that the macros xQueueSendFromISR(), * xQueueSendToFrontFromISR() and xQueueSendToBackFromISR() be used in place * of calling this function directly. * * 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; portBASE_TYPE 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 */ signed portBASE_TYPE xQueueGenericSendFromISR( xQueueHandle xQueue, const void * const pvItemToQueue, signed portBASE_TYPE *pxHigherPriorityTaskWoken, portBASE_TYPE xCopyPosition ) PRIVILEGED_FUNCTION; /** * queue. h * <pre> portBASE_TYPE xQueueReceiveFromISR( xQueueHandle xQueue, void *pvBuffer, portBASE_TYPE *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> xQueueHandle xQueue; // Function to create a queue and post some values. void vAFunction( void *pvParameters ) { char cValueToPost; const portTickType xBlockTime = ( portTickType )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 xBlockTime ticks. cValueToPost = 'a'; xQueueSend( xQueue, ( void * ) &cValueToPost, xBlockTime ); cValueToPost = 'b'; xQueueSend( xQueue, ( void * ) &cValueToPost, xBlockTime ); // ... keep posting characters ... this task may block when the queue // becomes full. cValueToPost = 'c'; xQueueSend( xQueue, ( void * ) &cValueToPost, xBlockTime ); } // ISR that outputs all the characters received on the queue. void vISR_Routine( void ) { portBASE_TYPE 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 */ signed portBASE_TYPE xQueueReceiveFromISR( xQueueHandle xQueue, void * const pvBuffer, signed portBASE_TYPE *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. */ signed portBASE_TYPE xQueueIsQueueEmptyFromISR( const xQueueHandle xQueue ) PRIVILEGED_FUNCTION; signed portBASE_TYPE xQueueIsQueueFullFromISR( const xQueueHandle xQueue ) PRIVILEGED_FUNCTION; unsigned portBASE_TYPE uxQueueMessagesWaitingFromISR( const xQueueHandle xQueue ) PRIVILEGED_FUNCTION; /* * xQueueAltGenericSend() is an alternative version of xQueueGenericSend(). * Likewise xQueueAltGenericReceive() is an alternative version of * xQueueGenericReceive(). * * The source code that implements the alternative (Alt) API is much * simpler because it executes everything from within a critical section. * This is the approach taken by many other RTOSes, but FreeRTOS.org has the * preferred fully featured API too. The fully featured API has more * complex code that takes longer to execute, but makes much less use of * critical sections. Therefore the alternative API sacrifices interrupt * responsiveness to gain execution speed, whereas the fully featured API * sacrifices execution speed to ensure better interrupt responsiveness. */ signed portBASE_TYPE xQueueAltGenericSend( xQueueHandle xQueue, const void * const pvItemToQueue, portTickType xTicksToWait, portBASE_TYPE xCopyPosition ); signed portBASE_TYPE xQueueAltGenericReceive( xQueueHandle xQueue, void * const pvBuffer, portTickType xTicksToWait, portBASE_TYPE xJustPeeking ); #define xQueueAltSendToFront( xQueue, pvItemToQueue, xTicksToWait ) xQueueAltGenericSend( ( xQueue ), ( pvItemToQueue ), ( xTicksToWait ), queueSEND_TO_FRONT ) #define xQueueAltSendToBack( xQueue, pvItemToQueue, xTicksToWait ) xQueueAltGenericSend( ( xQueue ), ( pvItemToQueue ), ( xTicksToWait ), queueSEND_TO_BACK ) #define xQueueAltReceive( xQueue, pvBuffer, xTicksToWait ) xQueueAltGenericReceive( ( xQueue ), ( pvBuffer ), ( xTicksToWait ), pdFALSE ) #define xQueueAltPeek( xQueue, pvBuffer, xTicksToWait ) xQueueAltGenericReceive( ( xQueue ), ( pvBuffer ), ( xTicksToWait ), pdTRUE ) /* * 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. */ signed portBASE_TYPE xQueueCRSendFromISR( xQueueHandle xQueue, const void *pvItemToQueue, signed portBASE_TYPE xCoRoutinePreviouslyWoken ); signed portBASE_TYPE xQueueCRReceiveFromISR( xQueueHandle xQueue, void *pvBuffer, signed portBASE_TYPE *pxTaskWoken ); signed portBASE_TYPE xQueueCRSend( xQueueHandle xQueue, const void *pvItemToQueue, portTickType xTicksToWait ); signed portBASE_TYPE xQueueCRReceive( xQueueHandle xQueue, void *pvBuffer, portTickType xTicksToWait ); /* * For internal use only. Use xSemaphoreCreateMutex(), * xSemaphoreCreateCounting() or xSemaphoreGetMutexHolder() instead of calling * these functions directly. */ xQueueHandle xQueueCreateMutex( unsigned char ucQueueType ) PRIVILEGED_FUNCTION; xQueueHandle xQueueCreateCountingSemaphore( unsigned portBASE_TYPE uxMaxCount, unsigned portBASE_TYPE uxInitialCount ) PRIVILEGED_FUNCTION; void* xQueueGetMutexHolder( xQueueHandle xSemaphore ) PRIVILEGED_FUNCTION; /* * For internal use only. Use xSemaphoreTakeMutexRecursive() or * xSemaphoreGiveMutexRecursive() instead of calling these functions directly. */ portBASE_TYPE xQueueTakeMutexRecursive( xQueueHandle xMutex, portTickType xBlockTime ) PRIVILEGED_FUNCTION; portBASE_TYPE xQueueGiveMutexRecursive( xQueueHandle pxMutex ) PRIVILEGED_FUNCTION; /* * Reset a queue back to its original empty state. pdPASS is returned if the * queue is successfully reset. pdFAIL is returned if the queue could not be * reset because there are tasks blocked on the queue waiting to either * receive from the queue or send to the queue. */ #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. */ #if configQUEUE_REGISTRY_SIZE > 0 void vQueueAddToRegistry( xQueueHandle xQueue, signed char *pcName ) PRIVILEGED_FUNCTION; #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( xQueueHandle xQueue ) PRIVILEGED_FUNCTION; #endif /* * Generic version of the queue creation function, which is in turn called by * any queue, semaphore or mutex creation function or macro. */ xQueueHandle xQueueGenericCreate( unsigned portBASE_TYPE uxQueueLength, unsigned portBASE_TYPE uxItemSize, unsigned char ucQueueType ) PRIVILEGED_FUNCTION; /* * 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. */ xQueueSetHandle xQueueCreateSet( unsigned portBASE_TYPE 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 xQueueSetMemberHandle 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. */ portBASE_TYPE xQueueAddToSet( xQueueSetMemberHandle xQueueOrSemaphore, xQueueSetHandle 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 xQueueSetMemberHandle 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. */ portBASE_TYPE xQueueRemoveFromSet( xQueueSetMemberHandle xQueueOrSemaphore, xQueueSetHandle 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 xBlockTimeTicks 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 xQueueSetMemberHandle type) contained in the queue set that contains data, * or the handle of a semaphore (cast to a xQueueSetMemberHandle 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. */ xQueueSetMemberHandle xQueueSelectFromSet( xQueueSetHandle xQueueSet, portTickType xBlockTimeTicks ) PRIVILEGED_FUNCTION; /* * A version of xQueueSelectFromSet() that can be used from an ISR. */ xQueueSetMemberHandle xQueueSelectFromSetFromISR( xQueueSetHandle xQueueSet ) PRIVILEGED_FUNCTION; /* Not public API functions. */ void vQueueWaitForMessageRestricted( xQueueHandle xQueue, portTickType xTicksToWait ) PRIVILEGED_FUNCTION; portBASE_TYPE xQueueGenericReset( xQueueHandle xQueue, portBASE_TYPE xNewQueue ) PRIVILEGED_FUNCTION; void vQueueSetQueueNumber( xQueueHandle xQueue, unsigned char ucQueueNumber ) PRIVILEGED_FUNCTION; unsigned char ucQueueGetQueueNumber( xQueueHandle xQueue ) PRIVILEGED_FUNCTION; unsigned char ucQueueGetQueueType( xQueueHandle xQueue ) PRIVILEGED_FUNCTION; #ifdef __cplusplus } #endif #endif /* QUEUE_H */