Google Git
Sign in
pigweed / third_party / github / FreeRTOS / FreeRTOS-Kernel / b6c0c51cbe74429fffb0ba48551907f4bb94eed6 / . / include / queue.h
blob: e892ed3d5e17a05e8e781bea4447f45925163647 [file] [log] [blame]
/*
* FreeRTOS Kernel <DEVELOPMENT BRANCH>
* Copyright (C) 2021 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* SPDX-License-Identifier: MIT
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* https://www.FreeRTOS.org
* https://github.com/FreeRTOS
*
*/
#ifndef QUEUE_H
#define QUEUE_H
#ifndef INC_FREERTOS_H
#error "include FreeRTOS.h" must appear in source files before "include queue.h"
#endif
/* *INDENT-OFF* */
#ifdef __cplusplus
extern "C" {
#endif
/* *INDENT-ON* */
#include "task.h"
/**
* 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.
*/
struct QueueDefinition; /* Using old naming convention so as not to break kernel aware debuggers. */
typedef struct QueueDefinition * 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 struct QueueDefinition * 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 struct QueueDefinition * 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
* @code{c}
* QueueHandle_t xQueueCreate(
* UBaseType_t uxQueueLength,
* UBaseType_t uxItemSize
* );
* @endcode
*
* 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
* https://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.
*
* https://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:
* @code{c}
* 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.
* }
* @endcode
* \defgroup xQueueCreate xQueueCreate
* \ingroup QueueManagement
*/
#if ( configSUPPORT_DYNAMIC_ALLOCATION == 1 )
#define xQueueCreate( uxQueueLength, uxItemSize ) xQueueGenericCreate( ( uxQueueLength ), ( uxItemSize ), ( queueQUEUE_TYPE_BASE ) )
#endif
/**
* queue. h
* @code{c}
* QueueHandle_t xQueueCreateStatic(
* UBaseType_t uxQueueLength,
* UBaseType_t uxItemSize,
* uint8_t *pucQueueStorage,
* StaticQueue_t *pxQueueBuffer
* );
* @endcode
*
* 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
* https://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.
*
* https://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 pucQueueStorage If uxItemSize is not zero then
* pucQueueStorage 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 pucQueueStorage 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:
* @code{c}
* 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.
* }
* @endcode
* \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
* @code{c}
* BaseType_t xQueueGetStaticBuffers( QueueHandle_t xQueue,
* uint8_t ** ppucQueueStorage,
* StaticQueue_t ** ppxStaticQueue );
* @endcode
*
* Retrieve pointers to a statically created queue's data structure buffer
* and storage area buffer. These are the same buffers that are supplied
* at the time of creation.
*
* @param xQueue The queue for which to retrieve the buffers.
*
* @param ppucQueueStorage Used to return a pointer to the queue's storage
* area buffer.
*
* @param ppxStaticQueue Used to return a pointer to the queue's data
* structure buffer.
*
* @return pdTRUE if buffers were retrieved, pdFALSE otherwise.
*
* \defgroup xQueueGetStaticBuffers xQueueGetStaticBuffers
* \ingroup QueueManagement
*/
#if ( configSUPPORT_STATIC_ALLOCATION == 1 )
#define xQueueGetStaticBuffers( xQueue, ppucQueueStorage, ppxStaticQueue ) xQueueGenericGetStaticBuffers( ( xQueue ), ( ppucQueueStorage ), ( ppxStaticQueue ) )
#endif /* configSUPPORT_STATIC_ALLOCATION */
/**
* queue. h
* @code{c}
* BaseType_t xQueueSendToFront(
* QueueHandle_t xQueue,
* const void *pvItemToQueue,
* TickType_t xTicksToWait
* );
* @endcode
*
* 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:
* @code{c}
* 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.
* }
* @endcode
* \defgroup xQueueSend xQueueSend
* \ingroup QueueManagement
*/
#define xQueueSendToFront( xQueue, pvItemToQueue, xTicksToWait ) \
xQueueGenericSend( ( xQueue ), ( pvItemToQueue ), ( xTicksToWait ), queueSEND_TO_FRONT )
/**
* queue. h
* @code{c}
* BaseType_t xQueueSendToBack(
* QueueHandle_t xQueue,
* const void *pvItemToQueue,
* TickType_t xTicksToWait
* );
* @endcode
*
* 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:
* @code{c}
* 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.
* }
* @endcode
* \defgroup xQueueSend xQueueSend
* \ingroup QueueManagement
*/
#define xQueueSendToBack( xQueue, pvItemToQueue, xTicksToWait ) \
xQueueGenericSend( ( xQueue ), ( pvItemToQueue ), ( xTicksToWait ), queueSEND_TO_BACK )
/**
* queue. h
* @code{c}
* BaseType_t xQueueSend(
* QueueHandle_t xQueue,
* const void * pvItemToQueue,
* TickType_t xTicksToWait
* );
* @endcode
*
* 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:
* @code{c}
* 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.
* }
* @endcode
* \defgroup xQueueSend xQueueSend
* \ingroup QueueManagement
*/
#define xQueueSend( xQueue, pvItemToQueue, xTicksToWait ) \
xQueueGenericSend( ( xQueue ), ( pvItemToQueue ), ( xTicksToWait ), queueSEND_TO_BACK )
/**
* queue. h
* @code{c}
* BaseType_t xQueueOverwrite(
* QueueHandle_t xQueue,
* const void * pvItemToQueue
* );
* @endcode
*
* 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:
* @code{c}
*
* 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!
* }
*
* // ...
* }
* @endcode
* \defgroup xQueueOverwrite xQueueOverwrite
* \ingroup QueueManagement
*/
#define xQueueOverwrite( xQueue, pvItemToQueue ) \
xQueueGenericSend( ( xQueue ), ( pvItemToQueue ), 0, queueOVERWRITE )
/**
* queue. h
* @code{c}
* BaseType_t xQueueGenericSend(
* QueueHandle_t xQueue,
* const void * pvItemToQueue,
* TickType_t xTicksToWait
* BaseType_t xCopyPosition
* );
* @endcode
*
* 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:
* @code{c}
* 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.
* }
* @endcode
* \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
* @code{c}
* BaseType_t xQueuePeek(
* QueueHandle_t xQueue,
* void * const pvBuffer,
* TickType_t xTicksToWait
* );
* @endcode
*
* 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:
* @code{c}
* 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.
* }
* @endcode
* \defgroup xQueuePeek xQueuePeek
* \ingroup QueueManagement
*/
BaseType_t xQueuePeek( QueueHandle_t xQueue,
void * const pvBuffer,
TickType_t xTicksToWait ) PRIVILEGED_FUNCTION;
/**
* queue. h
* @code{c}
* BaseType_t xQueuePeekFromISR(
* QueueHandle_t xQueue,
* void *pvBuffer,
* );
* @endcode
*
* 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
* @code{c}
* BaseType_t xQueueReceive(
* QueueHandle_t xQueue,
* void *pvBuffer,
* TickType_t xTicksToWait
* );
* @endcode
*
* 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:
* @code{c}
* 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.
* }
* @endcode
* \defgroup xQueueReceive xQueueReceive
* \ingroup QueueManagement
*/
BaseType_t xQueueReceive( QueueHandle_t xQueue,
void * const pvBuffer,
TickType_t xTicksToWait ) PRIVILEGED_FUNCTION;
/**
* queue. h
* @code{c}
* UBaseType_t uxQueueMessagesWaiting( const QueueHandle_t xQueue );
* @endcode
*
* 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
* @code{c}
* UBaseType_t uxQueueSpacesAvailable( const QueueHandle_t xQueue );
* @endcode
*
* 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
* @code{c}
* void vQueueDelete( QueueHandle_t xQueue );
* @endcode
*
* 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
* @code{c}
* BaseType_t xQueueSendToFrontFromISR(
* QueueHandle_t xQueue,
* const void *pvItemToQueue,
* BaseType_t *pxHigherPriorityTaskWoken
* );
* @endcode
*
* 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 xQueueSendToFrontFromISR() 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):
* @code{c}
* 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.
* xQueueSendToFrontFromISR( xRxQueue, &cIn, &xHigherPriorityTaskWoken );
*
* } while( portINPUT_BYTE( BUFFER_COUNT ) );
*
* // Now the buffer is empty we can switch context if necessary.
* if( xHigherPriorityTaskWoken )
* {
* taskYIELD ();
* }
* }
* @endcode
*
* \defgroup xQueueSendFromISR xQueueSendFromISR
* \ingroup QueueManagement
*/
#define xQueueSendToFrontFromISR( xQueue, pvItemToQueue, pxHigherPriorityTaskWoken ) \
xQueueGenericSendFromISR( ( xQueue ), ( pvItemToQueue ), ( pxHigherPriorityTaskWoken ), queueSEND_TO_FRONT )
/**
* queue. h
* @code{c}
* BaseType_t xQueueSendToBackFromISR(
* QueueHandle_t xQueue,
* const void *pvItemToQueue,
* BaseType_t *pxHigherPriorityTaskWoken
* );
* @endcode
*
* 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):
* @code{c}
* 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 ();
* }
* }
* @endcode
*
* \defgroup xQueueSendFromISR xQueueSendFromISR
* \ingroup QueueManagement
*/
#define xQueueSendToBackFromISR( xQueue, pvItemToQueue, pxHigherPriorityTaskWoken ) \
xQueueGenericSendFromISR( ( xQueue ), ( pvItemToQueue ), ( pxHigherPriorityTaskWoken ), queueSEND_TO_BACK )
/**
* queue. h
* @code{c}
* BaseType_t xQueueOverwriteFromISR(
* QueueHandle_t xQueue,
* const void * pvItemToQueue,
* BaseType_t *pxHigherPriorityTaskWoken
* );
* @endcode
*
* 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:
* @code{c}
*
* 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.
* // The macro used is port specific and will be either
* // portYIELD_FROM_ISR() or portEND_SWITCHING_ISR() - refer to the documentation
* // page for the port being used.
* portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
* }
* }
* @endcode
* \defgroup xQueueOverwriteFromISR xQueueOverwriteFromISR
* \ingroup QueueManagement
*/
#define xQueueOverwriteFromISR( xQueue, pvItemToQueue, pxHigherPriorityTaskWoken ) \
xQueueGenericSendFromISR( ( xQueue ), ( pvItemToQueue ), ( pxHigherPriorityTaskWoken ), queueOVERWRITE )
/**
* queue. h
* @code{c}
* BaseType_t xQueueSendFromISR(
* QueueHandle_t xQueue,
* const void *pvItemToQueue,
* BaseType_t *pxHigherPriorityTaskWoken
* );
* @endcode
*
* 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):
* @code{c}
* 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 )
* {
* // As xHigherPriorityTaskWoken is now set to pdTRUE then a context
* // switch should be requested. The macro used is port specific and
* // will be either portYIELD_FROM_ISR() or portEND_SWITCHING_ISR() -
* // refer to the documentation page for the port being used.
* portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
* }
* }
* @endcode
*
* \defgroup xQueueSendFromISR xQueueSendFromISR
* \ingroup QueueManagement
*/
#define xQueueSendFromISR( xQueue, pvItemToQueue, pxHigherPriorityTaskWoken ) \
xQueueGenericSendFromISR( ( xQueue ), ( pvItemToQueue ), ( pxHigherPriorityTaskWoken ), queueSEND_TO_BACK )
/**
* queue. h
* @code{c}
* BaseType_t xQueueGenericSendFromISR(
* QueueHandle_t xQueue,
* const void *pvItemToQueue,
* BaseType_t *pxHigherPriorityTaskWoken,
* BaseType_t xCopyPosition
* );
* @endcode
*
* 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):
* @code{c}
* 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.
* if( xHigherPriorityTaskWokenByPost )
* {
* // As xHigherPriorityTaskWokenByPost is now set to pdTRUE then a context
* // switch should be requested. The macro used is port specific and
* // will be either portYIELD_FROM_ISR() or portEND_SWITCHING_ISR() -
* // refer to the documentation page for the port being used.
* portYIELD_FROM_ISR( xHigherPriorityTaskWokenByPost );
* }
* }
* @endcode
*
* \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
* @code{c}
* BaseType_t xQueueReceiveFromISR(
* QueueHandle_t xQueue,
* void *pvBuffer,
* BaseType_t *pxTaskWoken
* );
* @endcode
*
* 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 pxHigherPriorityTaskWoken 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:
* @code{c}
*
* 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 xTaskWokenByReceive will have been set to
* // pdTRUE. No matter how many times this loop iterates only one
* // task will be woken.
* }
*
* if( xTaskWokenByReceive != ( char ) pdFALSE;
* {
* taskYIELD ();
* }
* }
* @endcode
* \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 within 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;
#if ( configUSE_CO_ROUTINES == 1 )
/*
* 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 );
#endif /* if ( configUSE_CO_ROUTINES == 1 ) */
/*
* For internal use only. Use xSemaphoreCreateMutex(),
* xSemaphoreCreateCounting() or xSemaphoreGetMutexHolder() instead of calling
* these functions directly.
*/
QueueHandle_t xQueueCreateMutex( const uint8_t ucQueueType ) PRIVILEGED_FUNCTION;
#if ( configSUPPORT_STATIC_ALLOCATION == 1 )
QueueHandle_t xQueueCreateMutexStatic( const uint8_t ucQueueType,
StaticQueue_t * pxStaticQueue ) PRIVILEGED_FUNCTION;
#endif
#if ( configUSE_COUNTING_SEMAPHORES == 1 )
QueueHandle_t xQueueCreateCountingSemaphore( const UBaseType_t uxMaxCount,
const UBaseType_t uxInitialCount ) PRIVILEGED_FUNCTION;
#endif
#if ( ( configUSE_COUNTING_SEMAPHORES == 1 ) && ( configSUPPORT_STATIC_ALLOCATION == 1 ) )
QueueHandle_t xQueueCreateCountingSemaphoreStatic( const UBaseType_t uxMaxCount,
const UBaseType_t uxInitialCount,
StaticQueue_t * pxStaticQueue ) PRIVILEGED_FUNCTION;
#endif
BaseType_t xQueueSemaphoreTake( QueueHandle_t xQueue,
TickType_t xTicksToWait ) PRIVILEGED_FUNCTION;
#if ( ( configUSE_MUTEXES == 1 ) && ( INCLUDE_xSemaphoreGetMutexHolder == 1 ) )
TaskHandle_t xQueueGetMutexHolder( QueueHandle_t xSemaphore ) PRIVILEGED_FUNCTION;
TaskHandle_t xQueueGetMutexHolderFromISR( QueueHandle_t xSemaphore ) PRIVILEGED_FUNCTION;
#endif
/*
* For internal use only. Use xSemaphoreTakeRecursive() or
* xSemaphoreGiveRecursive() instead of calling these functions directly.
*/
BaseType_t xQueueTakeMutexRecursive( QueueHandle_t xMutex,
TickType_t xTicksToWait ) PRIVILEGED_FUNCTION;
BaseType_t xQueueGiveMutexRecursive( QueueHandle_t xMutex ) 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 affect the number of queues, semaphores and mutexes that can be
* created - just the number that the registry can hold.
*
* If vQueueAddToRegistry is called more than once with the same xQueue
* parameter, the registry will store the pcQueueName parameter from the
* most recent call to vQueueAddToRegistry.
*
* @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 pcQueueName 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 * pcQueueName ) 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( 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;
#endif
/*
* Generic version of the function used to create 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 create 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
/*
* Generic version of the function used to retrieve the buffers of statically
* created queues. This is called by other functions and macros that retrieve
* the buffers of other statically created RTOS objects that use the queue
* structure as their base.
*/
#if ( configSUPPORT_STATIC_ALLOCATION == 1 )
BaseType_t xQueueGenericGetStaticBuffers( QueueHandle_t xQueue,
uint8_t ** ppucQueueStorage,
StaticQueue_t ** ppxStaticQueue ) 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 https://www.FreeRTOS.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.
*/
#if ( ( configUSE_QUEUE_SETS == 1 ) && ( configSUPPORT_DYNAMIC_ALLOCATION == 1 ) )
QueueSetHandle_t xQueueCreateSet( const UBaseType_t uxEventQueueLength ) PRIVILEGED_FUNCTION;
#endif
/*
* 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.
*/
#if ( configUSE_QUEUE_SETS == 1 )
BaseType_t xQueueAddToSet( QueueSetMemberHandle_t xQueueOrSemaphore,
QueueSetHandle_t xQueueSet ) PRIVILEGED_FUNCTION;
#endif
/*
* 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.
*/
#if ( configUSE_QUEUE_SETS == 1 )
BaseType_t xQueueRemoveFromSet( QueueSetMemberHandle_t xQueueOrSemaphore,
QueueSetHandle_t xQueueSet ) PRIVILEGED_FUNCTION;
#endif
/*
* 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 https://www.FreeRTOS.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.
*/
#if ( configUSE_QUEUE_SETS == 1 )
QueueSetMemberHandle_t xQueueSelectFromSet( QueueSetHandle_t xQueueSet,
const TickType_t xTicksToWait ) PRIVILEGED_FUNCTION;
#endif
/*
* A version of xQueueSelectFromSet() that can be used from an ISR.
*/
#if ( configUSE_QUEUE_SETS == 1 )
QueueSetMemberHandle_t xQueueSelectFromSetFromISR( QueueSetHandle_t xQueueSet ) PRIVILEGED_FUNCTION;
#endif
/* 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;
#if ( configUSE_TRACE_FACILITY == 1 )
void vQueueSetQueueNumber( QueueHandle_t xQueue,
UBaseType_t uxQueueNumber ) PRIVILEGED_FUNCTION;
#endif
#if ( configUSE_TRACE_FACILITY == 1 )
UBaseType_t uxQueueGetQueueNumber( QueueHandle_t xQueue ) PRIVILEGED_FUNCTION;
#endif
#if ( configUSE_TRACE_FACILITY == 1 )
uint8_t ucQueueGetQueueType( QueueHandle_t xQueue ) PRIVILEGED_FUNCTION;
#endif
UBaseType_t uxQueueGetQueueItemSize( QueueHandle_t xQueue ) PRIVILEGED_FUNCTION;
UBaseType_t uxQueueGetQueueLength( QueueHandle_t xQueue ) PRIVILEGED_FUNCTION;
/* *INDENT-OFF* */
#ifdef __cplusplus
}
#endif
/* *INDENT-ON* */
#endif /* QUEUE_H */