/*
FreeRTOS V8.0.1 - Copyright (C) 2014 Real Time Engineers Ltd.
All rights reserved
VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
***************************************************************************
* *
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* 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 *
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***************************************************************************
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 !<<
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>>! outside of the FreeRTOS kernel. !<<
FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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FOR A PARTICULAR PURPOSE. Full license text is available from the following
link: http://www.freertos.org/a00114.html
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***************************************************************************
* *
* Having a problem? Start by reading the FAQ "My application does *
* not run, what could be wrong?" *
* *
* http://www.FreeRTOS.org/FAQHelp.html *
* *
***************************************************************************
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*/
#ifndef QUEUE_H
#define QUEUE_H
#ifndef INC_FREERTOS_H
#error "include FreeRTOS.h" must appear in source files before "include queue.h"
#endif
#ifdef __cplusplus
extern "C" {
#endif
/**
* Type by which queues are referenced. For example, a call to xQueueCreate()
* returns an QueueHandle_t variable that can then be used as a parameter to
* xQueueSend(), xQueueReceive(), etc.
*/
typedef void * QueueHandle_t;
/**
* Type by which queue sets are referenced. For example, a call to
* xQueueCreateSet() returns an xQueueSet variable that can then be used as a
* parameter to xQueueSelectFromSet(), xQueueAddToSet(), etc.
*/
typedef void * QueueSetHandle_t;
/**
* Queue sets can contain both queues and semaphores, so the
* QueueSetMemberHandle_t is defined as a type to be used where a parameter or
* return value can be either an QueueHandle_t or an SemaphoreHandle_t.
*/
typedef void * QueueSetMemberHandle_t;
/* For internal use only. */
#define queueSEND_TO_BACK ( ( BaseType_t ) 0 )
#define queueSEND_TO_FRONT ( ( BaseType_t ) 1 )
#define queueOVERWRITE ( ( BaseType_t ) 2 )
/* For internal use only. These definitions *must* match those in queue.c. */
#define queueQUEUE_TYPE_BASE ( ( uint8_t ) 0U )
#define queueQUEUE_TYPE_SET ( ( uint8_t ) 0U )
#define queueQUEUE_TYPE_MUTEX ( ( uint8_t ) 1U )
#define queueQUEUE_TYPE_COUNTING_SEMAPHORE ( ( uint8_t ) 2U )
#define queueQUEUE_TYPE_BINARY_SEMAPHORE ( ( uint8_t ) 3U )
#define queueQUEUE_TYPE_RECURSIVE_MUTEX ( ( uint8_t ) 4U )
/**
* queue. h
*
QueueHandle_t xQueueCreate(
UBaseType_t uxQueueLength,
UBaseType_t uxItemSize
);
*
*
* 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:
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.
}
* \defgroup xQueueCreate xQueueCreate
* \ingroup QueueManagement
*/
#define xQueueCreate( uxQueueLength, uxItemSize ) xQueueGenericCreate( uxQueueLength, uxItemSize, queueQUEUE_TYPE_BASE )
/**
* queue. h
*
BaseType_t xQueueSendToToFront(
QueueHandle_t xQueue,
const void *pvItemToQueue,
TickType_t xTicksToWait
);
*
*
* This is a macro that calls xQueueGenericSend().
*
* Post an item to the front of a queue. The item is queued by copy, not by
* reference. This function must not be called from an interrupt service
* routine. See xQueueSendFromISR () for an alternative which may be used
* in an ISR.
*
* @param xQueue The handle to the queue on which the item is to be posted.
*
* @param pvItemToQueue A pointer to the item that is to be placed on the
* queue. The size of the items the queue will hold was defined when the
* queue was created, so this many bytes will be copied from pvItemToQueue
* into the queue storage area.
*
* @param xTicksToWait The maximum amount of time the task should block
* waiting for space to become available on the queue, should it already
* be full. The call will return immediately if this is set to 0 and the
* queue is full. The time is defined in tick periods so the constant
* portTICK_PERIOD_MS should be used to convert to real time if this is required.
*
* @return pdTRUE if the item was successfully posted, otherwise errQUEUE_FULL.
*
* Example usage:
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.
}
* \defgroup xQueueSend xQueueSend
* \ingroup QueueManagement
*/
#define xQueueSendToFront( xQueue, pvItemToQueue, xTicksToWait ) xQueueGenericSend( ( xQueue ), ( pvItemToQueue ), ( xTicksToWait ), queueSEND_TO_FRONT )
/**
* queue. h
*
BaseType_t xQueueSendToBack(
QueueHandle_t xQueue,
const void *pvItemToQueue,
TickType_t xTicksToWait
);
*
*
* 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:
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.
}
* \defgroup xQueueSend xQueueSend
* \ingroup QueueManagement
*/
#define xQueueSendToBack( xQueue, pvItemToQueue, xTicksToWait ) xQueueGenericSend( ( xQueue ), ( pvItemToQueue ), ( xTicksToWait ), queueSEND_TO_BACK )
/**
* queue. h
*
BaseType_t xQueueSend(
QueueHandle_t xQueue,
const void * pvItemToQueue,
TickType_t xTicksToWait
);
*
*
* 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:
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.
}
* \defgroup xQueueSend xQueueSend
* \ingroup QueueManagement
*/
#define xQueueSend( xQueue, pvItemToQueue, xTicksToWait ) xQueueGenericSend( ( xQueue ), ( pvItemToQueue ), ( xTicksToWait ), queueSEND_TO_BACK )
/**
* queue. h
*
BaseType_t xQueueOverwrite(
QueueHandle_t xQueue,
const void * pvItemToQueue
);
*
*
* 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:
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!
}
// ...
}
* \defgroup xQueueOverwrite xQueueOverwrite
* \ingroup QueueManagement
*/
#define xQueueOverwrite( xQueue, pvItemToQueue ) xQueueGenericSend( ( xQueue ), ( pvItemToQueue ), 0, queueOVERWRITE )
/**
* queue. h
*
BaseType_t xQueueGenericSend(
QueueHandle_t xQueue,
const void * pvItemToQueue,
TickType_t xTicksToWait
BaseType_t xCopyPosition
);
*
*
* 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:
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.
}
* \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
*
BaseType_t xQueuePeek(
QueueHandle_t xQueue,
void *pvBuffer,
TickType_t xTicksToWait
);
*
* This is a macro that calls the xQueueGenericReceive() function.
*
* Receive an item from a queue without removing the item from the queue.
* The item is received by copy so a buffer of adequate size must be
* provided. The number of bytes copied into the buffer was defined when
* the queue was created.
*
* Successfully received items remain on the queue so will be returned again
* by the next call, or a call to xQueueReceive().
*
* This macro must not be used in an interrupt service routine. See
* xQueuePeekFromISR() for an alternative that can be called from an interrupt
* service routine.
*
* @param xQueue The handle to the queue from which the item is to be
* received.
*
* @param pvBuffer Pointer to the buffer into which the received item will
* be copied.
*
* @param xTicksToWait The maximum amount of time the task should block
* waiting for an item to receive should the queue be empty at the time
* of the call. The time is defined in tick periods so the constant
* portTICK_PERIOD_MS should be used to convert to real time if this is required.
* xQueuePeek() will return immediately if xTicksToWait is 0 and the queue
* is empty.
*
* @return pdTRUE if an item was successfully received from the queue,
* otherwise pdFALSE.
*
* Example usage:
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.
}
* \defgroup xQueueReceive xQueueReceive
* \ingroup QueueManagement
*/
#define xQueuePeek( xQueue, pvBuffer, xTicksToWait ) xQueueGenericReceive( ( xQueue ), ( pvBuffer ), ( xTicksToWait ), pdTRUE )
/**
* queue. h
*
BaseType_t xQueuePeekFromISR(
QueueHandle_t xQueue,
void *pvBuffer,
);
*
* 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
*
BaseType_t xQueueReceive(
QueueHandle_t xQueue,
void *pvBuffer,
TickType_t xTicksToWait
);
*
* This is a macro that calls the xQueueGenericReceive() function.
*
* Receive an item from a queue. The item is received by copy so a buffer of
* adequate size must be provided. The number of bytes copied into the buffer
* was defined when the queue was created.
*
* Successfully received items are removed from the queue.
*
* This function must not be used in an interrupt service routine. See
* xQueueReceiveFromISR for an alternative that can.
*
* @param xQueue The handle to the queue from which the item is to be
* received.
*
* @param pvBuffer Pointer to the buffer into which the received item will
* be copied.
*
* @param xTicksToWait The maximum amount of time the task should block
* waiting for an item to receive should the queue be empty at the time
* of the call. xQueueReceive() will return immediately if xTicksToWait
* is zero and the queue is empty. The time is defined in tick periods so the
* constant portTICK_PERIOD_MS should be used to convert to real time if this is
* required.
*
* @return pdTRUE if an item was successfully received from the queue,
* otherwise pdFALSE.
*
* Example usage:
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.
}
* \defgroup xQueueReceive xQueueReceive
* \ingroup QueueManagement
*/
#define xQueueReceive( xQueue, pvBuffer, xTicksToWait ) xQueueGenericReceive( ( xQueue ), ( pvBuffer ), ( xTicksToWait ), pdFALSE )
/**
* queue. h
*
BaseType_t xQueueGenericReceive(
QueueHandle_t xQueue,
void *pvBuffer,
TickType_t xTicksToWait
BaseType_t xJustPeek
);
*
* It is preferred that the macro xQueueReceive() be used rather than calling
* this function directly.
*
* Receive an item from a queue. The item is received by copy so a buffer of
* adequate size must be provided. The number of bytes copied into the buffer
* was defined when the queue was created.
*
* This function must not be used in an interrupt service routine. See
* xQueueReceiveFromISR for an alternative that can.
*
* @param xQueue The handle to the queue from which the item is to be
* received.
*
* @param pvBuffer Pointer to the buffer into which the received item will
* be copied.
*
* @param xTicksToWait The maximum amount of time the task should block
* waiting for an item to receive should the queue be empty at the time
* of the call. The time is defined in tick periods so the constant
* portTICK_PERIOD_MS should be used to convert to real time if this is required.
* xQueueGenericReceive() will return immediately if the queue is empty and
* xTicksToWait is 0.
*
* @param xJustPeek When set to true, the item received from the queue is not
* actually removed from the queue - meaning a subsequent call to
* xQueueReceive() will return the same item. When set to false, the item
* being received from the queue is also removed from the queue.
*
* @return pdTRUE if an item was successfully received from the queue,
* otherwise pdFALSE.
*
* Example usage:
struct AMessage
{
char ucMessageID;
char ucData[ 20 ];
} xMessage;
QueueHandle_t xQueue;
// Task to create a queue and post a value.
void vATask( void *pvParameters )
{
struct AMessage *pxMessage;
// Create a queue capable of containing 10 pointers to AMessage structures.
// These should be passed by pointer as they contain a lot of data.
xQueue = xQueueCreate( 10, sizeof( struct AMessage * ) );
if( xQueue == 0 )
{
// Failed to create the queue.
}
// ...
// Send a pointer to a struct AMessage object. Don't block if the
// queue is already full.
pxMessage = & xMessage;
xQueueSend( xQueue, ( void * ) &pxMessage, ( TickType_t ) 0 );
// ... Rest of task code.
}
// Task to receive from the queue.
void vADifferentTask( void *pvParameters )
{
struct AMessage *pxRxedMessage;
if( xQueue != 0 )
{
// Receive a message on the created queue. Block for 10 ticks if a
// message is not immediately available.
if( xQueueGenericReceive( xQueue, &( pxRxedMessage ), ( TickType_t ) 10 ) )
{
// pcRxedMessage now points to the struct AMessage variable posted
// by vATask.
}
}
// ... Rest of task code.
}
* \defgroup xQueueReceive xQueueReceive
* \ingroup QueueManagement
*/
BaseType_t xQueueGenericReceive( QueueHandle_t xQueue, void * const pvBuffer, TickType_t xTicksToWait, const BaseType_t xJustPeek ) PRIVILEGED_FUNCTION;
/**
* queue. h
* UBaseType_t uxQueueMessagesWaiting( const QueueHandle_t xQueue );
*
* 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
* UBaseType_t uxQueueSpacesAvailable( const QueueHandle_t xQueue );
*
* 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
* void vQueueDelete( QueueHandle_t xQueue );
*
* 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
*
BaseType_t xQueueSendToFrontFromISR(
QueueHandle_t xQueue,
const void *pvItemToQueue,
BaseType_t *pxHigherPriorityTaskWoken
);
*
* 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):
void vBufferISR( void )
{
char cIn;
BaseType_t xHigherPrioritTaskWoken;
// We have not woken a task at the start of the ISR.
xHigherPriorityTaskWoken = pdFALSE;
// Loop until the buffer is empty.
do
{
// Obtain a byte from the buffer.
cIn = portINPUT_BYTE( RX_REGISTER_ADDRESS );
// Post the byte.
xQueueSendToFrontFromISR( xRxQueue, &cIn, &xHigherPriorityTaskWoken );
} while( portINPUT_BYTE( BUFFER_COUNT ) );
// Now the buffer is empty we can switch context if necessary.
if( xHigherPriorityTaskWoken )
{
taskYIELD ();
}
}
*
* \defgroup xQueueSendFromISR xQueueSendFromISR
* \ingroup QueueManagement
*/
#define xQueueSendToFrontFromISR( xQueue, pvItemToQueue, pxHigherPriorityTaskWoken ) xQueueGenericSendFromISR( ( xQueue ), ( pvItemToQueue ), ( pxHigherPriorityTaskWoken ), queueSEND_TO_FRONT )
/**
* queue. h
*
BaseType_t xQueueSendToBackFromISR(
QueueHandle_t xQueue,
const void *pvItemToQueue,
BaseType_t *pxHigherPriorityTaskWoken
);
*
* 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):
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 ();
}
}
*
* \defgroup xQueueSendFromISR xQueueSendFromISR
* \ingroup QueueManagement
*/
#define xQueueSendToBackFromISR( xQueue, pvItemToQueue, pxHigherPriorityTaskWoken ) xQueueGenericSendFromISR( ( xQueue ), ( pvItemToQueue ), ( pxHigherPriorityTaskWoken ), queueSEND_TO_BACK )
/**
* queue. h
*
BaseType_t xQueueOverwriteFromISR(
QueueHandle_t xQueue,
const void * pvItemToQueue,
BaseType_t *pxHigherPriorityTaskWoken
);
*
*
* 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:
QueueHandle_t xQueue;
void vFunction( void *pvParameters )
{
// Create a queue to hold one uint32_t value. It is strongly
// recommended *not* to use xQueueOverwriteFromISR() on queues that can
// contain more than one value, and doing so will trigger an assertion
// if configASSERT() is defined.
xQueue = xQueueCreate( 1, sizeof( uint32_t ) );
}
void vAnInterruptHandler( void )
{
// xHigherPriorityTaskWoken must be set to pdFALSE before it is used.
BaseType_t xHigherPriorityTaskWoken = pdFALSE;
uint32_t ulVarToSend, ulValReceived;
// Write the value 10 to the queue using xQueueOverwriteFromISR().
ulVarToSend = 10;
xQueueOverwriteFromISR( xQueue, &ulVarToSend, &xHigherPriorityTaskWoken );
// The queue is full, but calling xQueueOverwriteFromISR() again will still
// pass because the value held in the queue will be overwritten with the
// new value.
ulVarToSend = 100;
xQueueOverwriteFromISR( xQueue, &ulVarToSend, &xHigherPriorityTaskWoken );
// Reading from the queue will now return 100.
// ...
if( xHigherPrioritytaskWoken == pdTRUE )
{
// Writing to the queue caused a task to unblock and the unblocked task
// has a priority higher than or equal to the priority of the currently
// executing task (the task this interrupt interrupted). Perform a context
// switch so this interrupt returns directly to the unblocked task.
portYIELD_FROM_ISR(); // or portEND_SWITCHING_ISR() depending on the port.
}
}
* \defgroup xQueueOverwriteFromISR xQueueOverwriteFromISR
* \ingroup QueueManagement
*/
#define xQueueOverwriteFromISR( xQueue, pvItemToQueue, pxHigherPriorityTaskWoken ) xQueueGenericSendFromISR( ( xQueue ), ( pvItemToQueue ), ( pxHigherPriorityTaskWoken ), queueOVERWRITE )
/**
* queue. h
*
BaseType_t xQueueSendFromISR(
QueueHandle_t xQueue,
const void *pvItemToQueue,
BaseType_t *pxHigherPriorityTaskWoken
);
*
* 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):
void vBufferISR( void )
{
char cIn;
BaseType_t xHigherPriorityTaskWoken;
// We have not woken a task at the start of the ISR.
xHigherPriorityTaskWoken = pdFALSE;
// Loop until the buffer is empty.
do
{
// Obtain a byte from the buffer.
cIn = portINPUT_BYTE( RX_REGISTER_ADDRESS );
// Post the byte.
xQueueSendFromISR( xRxQueue, &cIn, &xHigherPriorityTaskWoken );
} while( portINPUT_BYTE( BUFFER_COUNT ) );
// Now the buffer is empty we can switch context if necessary.
if( xHigherPriorityTaskWoken )
{
// Actual macro used here is port specific.
portYIELD_FROM_ISR ();
}
}
*
* \defgroup xQueueSendFromISR xQueueSendFromISR
* \ingroup QueueManagement
*/
#define xQueueSendFromISR( xQueue, pvItemToQueue, pxHigherPriorityTaskWoken ) xQueueGenericSendFromISR( ( xQueue ), ( pvItemToQueue ), ( pxHigherPriorityTaskWoken ), queueSEND_TO_BACK )
/**
* queue. h
*
BaseType_t xQueueGenericSendFromISR(
QueueHandle_t xQueue,
const void *pvItemToQueue,
BaseType_t *pxHigherPriorityTaskWoken,
BaseType_t xCopyPosition
);
*
* 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):
void vBufferISR( void )
{
char cIn;
BaseType_t xHigherPriorityTaskWokenByPost;
// We have not woken a task at the start of the ISR.
xHigherPriorityTaskWokenByPost = pdFALSE;
// Loop until the buffer is empty.
do
{
// Obtain a byte from the buffer.
cIn = portINPUT_BYTE( RX_REGISTER_ADDRESS );
// Post each byte.
xQueueGenericSendFromISR( xRxQueue, &cIn, &xHigherPriorityTaskWokenByPost, queueSEND_TO_BACK );
} while( portINPUT_BYTE( BUFFER_COUNT ) );
// Now the buffer is empty we can switch context if necessary. Note that the
// name of the yield function required is port specific.
if( xHigherPriorityTaskWokenByPost )
{
taskYIELD_YIELD_FROM_ISR();
}
}
*
* \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;
/**
* queue. h
*
BaseType_t xQueueReceiveFromISR(
QueueHandle_t xQueue,
void *pvBuffer,
BaseType_t *pxTaskWoken
);
*
*
* 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:
QueueHandle_t xQueue;
// Function to create a queue and post some values.
void vAFunction( void *pvParameters )
{
char cValueToPost;
const TickType_t xTicksToWait = ( TickType_t )0xff;
// Create a queue capable of containing 10 characters.
xQueue = xQueueCreate( 10, sizeof( char ) );
if( xQueue == 0 )
{
// Failed to create the queue.
}
// ...
// Post some characters that will be used within an ISR. If the queue
// is full then this task will block for xTicksToWait ticks.
cValueToPost = 'a';
xQueueSend( xQueue, ( void * ) &cValueToPost, xTicksToWait );
cValueToPost = 'b';
xQueueSend( xQueue, ( void * ) &cValueToPost, xTicksToWait );
// ... keep posting characters ... this task may block when the queue
// becomes full.
cValueToPost = 'c';
xQueueSend( xQueue, ( void * ) &cValueToPost, xTicksToWait );
}
// ISR that outputs all the characters received on the queue.
void vISR_Routine( void )
{
BaseType_t xTaskWokenByReceive = pdFALSE;
char cRxedChar;
while( xQueueReceiveFromISR( xQueue, ( void * ) &cRxedChar, &xTaskWokenByReceive) )
{
// A character was received. Output the character now.
vOutputCharacter( cRxedChar );
// If removing the character from the queue woke the task that was
// posting onto the queue cTaskWokenByReceive will have been set to
// pdTRUE. No matter how many times this loop iterates only one
// task will be woken.
}
if( cTaskWokenByPost != ( char ) pdFALSE;
{
taskYIELD ();
}
}
* \defgroup xQueueReceiveFromISR xQueueReceiveFromISR
* \ingroup QueueManagement
*/
BaseType_t xQueueReceiveFromISR( QueueHandle_t xQueue, void * const pvBuffer, BaseType_t * const pxHigherPriorityTaskWoken ) PRIVILEGED_FUNCTION;
/*
* Utilities to query queues that are safe to use from an ISR. These utilities
* should be used only from witin an ISR, or within a critical section.
*/
BaseType_t xQueueIsQueueEmptyFromISR( const QueueHandle_t xQueue ) PRIVILEGED_FUNCTION;
BaseType_t xQueueIsQueueFullFromISR( const QueueHandle_t xQueue ) PRIVILEGED_FUNCTION;
UBaseType_t uxQueueMessagesWaitingFromISR( const QueueHandle_t xQueue ) PRIVILEGED_FUNCTION;
/*
* 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.
*/
BaseType_t xQueueAltGenericSend( QueueHandle_t xQueue, const void * const pvItemToQueue, TickType_t xTicksToWait, BaseType_t xCopyPosition );
BaseType_t xQueueAltGenericReceive( QueueHandle_t xQueue, void * const pvBuffer, TickType_t xTicksToWait, BaseType_t 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.
*/
BaseType_t xQueueCRSendFromISR( QueueHandle_t xQueue, const void *pvItemToQueue, BaseType_t xCoRoutinePreviouslyWoken );
BaseType_t xQueueCRReceiveFromISR( QueueHandle_t xQueue, void *pvBuffer, BaseType_t *pxTaskWoken );
BaseType_t xQueueCRSend( QueueHandle_t xQueue, const void *pvItemToQueue, TickType_t xTicksToWait );
BaseType_t xQueueCRReceive( QueueHandle_t xQueue, void *pvBuffer, TickType_t xTicksToWait );
/*
* For internal use only. Use xSemaphoreCreateMutex(),
* xSemaphoreCreateCounting() or xSemaphoreGetMutexHolder() instead of calling
* these functions directly.
*/
QueueHandle_t xQueueCreateMutex( const uint8_t ucQueueType ) PRIVILEGED_FUNCTION;
QueueHandle_t xQueueCreateCountingSemaphore( const UBaseType_t uxMaxCount, const UBaseType_t uxInitialCount ) PRIVILEGED_FUNCTION;
void* xQueueGetMutexHolder( QueueHandle_t xSemaphore ) PRIVILEGED_FUNCTION;
/*
* For internal use only. Use xSemaphoreTakeMutexRecursive() or
* xSemaphoreGiveMutexRecursive() instead of calling these functions directly.
*/
BaseType_t xQueueTakeMutexRecursive( QueueHandle_t xMutex, TickType_t xTicksToWait ) PRIVILEGED_FUNCTION;
BaseType_t xQueueGiveMutexRecursive( QueueHandle_t pxMutex ) PRIVILEGED_FUNCTION;
/*
* Reset a queue back to its original empty state. 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. The queue registry only
* stores a pointer to the string - so the string must be persistent (global or
* preferably in ROM/Flash), not on the stack.
*/
#if configQUEUE_REGISTRY_SIZE > 0
void vQueueAddToRegistry( QueueHandle_t xQueue, const char *pcName ) PRIVILEGED_FUNCTION; /*lint !e971 Unqualified char types are allowed for strings and single characters only. */
#endif
/*
* The registry is provided as a means for kernel aware debuggers to
* locate queues, semaphores and mutexes. Call vQueueAddToRegistry() add
* a queue, semaphore or mutex handle to the registry if you want the handle
* to be available to a kernel aware debugger, and vQueueUnregisterQueue() to
* remove the queue, semaphore or mutex from the register. If you are not using
* a kernel aware debugger then this function can be ignored.
*
* @param xQueue The handle of the queue being removed from the registry.
*/
#if configQUEUE_REGISTRY_SIZE > 0
void vQueueUnregisterQueue( QueueHandle_t xQueue ) PRIVILEGED_FUNCTION;
#endif
/*
* Generic version of the queue creation function, which is in turn called by
* any queue, semaphore or mutex creation function or macro.
*/
QueueHandle_t xQueueGenericCreate( const UBaseType_t uxQueueLength, const UBaseType_t uxItemSize, const uint8_t 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.
*/
QueueSetHandle_t xQueueCreateSet( const UBaseType_t uxEventQueueLength ) PRIVILEGED_FUNCTION;
/*
* Adds a queue or semaphore to a queue set that was previously created by a
* call to xQueueCreateSet().
*
* See FreeRTOS/Source/Demo/Common/Minimal/QueueSet.c for an example using this
* function.
*
* Note 1: A receive (in the case of a queue) or take (in the case of a
* semaphore) operation must not be performed on a member of a queue set unless
* a call to xQueueSelectFromSet() has first returned a handle to that set member.
*
* @param xQueueOrSemaphore The handle of the queue or semaphore being added to
* the queue set (cast to an QueueSetMemberHandle_t type).
*
* @param xQueueSet The handle of the queue set to which the queue or semaphore
* is being added.
*
* @return If the queue or semaphore was successfully added to the queue set
* then pdPASS is returned. If the queue could not be successfully added to the
* queue set because it is already a member of a different queue set then pdFAIL
* is returned.
*/
BaseType_t xQueueAddToSet( QueueSetMemberHandle_t xQueueOrSemaphore, QueueSetHandle_t xQueueSet ) PRIVILEGED_FUNCTION;
/*
* Removes a queue or semaphore from a queue set. A queue or semaphore can only
* be removed from a set if the queue or semaphore is empty.
*
* See FreeRTOS/Source/Demo/Common/Minimal/QueueSet.c for an example using this
* function.
*
* @param xQueueOrSemaphore The handle of the queue or semaphore being removed
* from the queue set (cast to an QueueSetMemberHandle_t type).
*
* @param xQueueSet The handle of the queue set in which the queue or semaphore
* is included.
*
* @return If the queue or semaphore was successfully removed from the queue set
* then pdPASS is returned. If the queue was not in the queue set, or the
* queue (or semaphore) was not empty, then pdFAIL is returned.
*/
BaseType_t xQueueRemoveFromSet( QueueSetMemberHandle_t xQueueOrSemaphore, QueueSetHandle_t xQueueSet ) PRIVILEGED_FUNCTION;
/*
* xQueueSelectFromSet() selects from the members of a queue set a queue or
* semaphore that either contains data (in the case of a queue) or is available
* to take (in the case of a semaphore). xQueueSelectFromSet() effectively
* allows a task to block (pend) on a read operation on all the queues and
* semaphores in a queue set simultaneously.
*
* See FreeRTOS/Source/Demo/Common/Minimal/QueueSet.c for an example using this
* function.
*
* Note 1: See the documentation on http://wwwFreeRTOS.org/RTOS-queue-sets.html
* for reasons why queue sets are very rarely needed in practice as there are
* simpler methods of blocking on multiple objects.
*
* Note 2: Blocking on a queue set that contains a mutex will not cause the
* mutex holder to inherit the priority of the blocked task.
*
* Note 3: A receive (in the case of a queue) or take (in the case of a
* semaphore) operation must not be performed on a member of a queue set unless
* a call to xQueueSelectFromSet() has first returned a handle to that set member.
*
* @param xQueueSet The queue set on which the task will (potentially) block.
*
* @param xTicksToWait The maximum time, in ticks, that the calling task will
* remain in the Blocked state (with other tasks executing) to wait for a member
* of the queue set to be ready for a successful queue read or semaphore take
* operation.
*
* @return xQueueSelectFromSet() will return the handle of a queue (cast to
* a QueueSetMemberHandle_t type) contained in the queue set that contains data,
* or the handle of a semaphore (cast to a QueueSetMemberHandle_t type) contained
* in the queue set that is available, or NULL if no such queue or semaphore
* exists before before the specified block time expires.
*/
QueueSetMemberHandle_t xQueueSelectFromSet( QueueSetHandle_t xQueueSet, const TickType_t xTicksToWait ) PRIVILEGED_FUNCTION;
/*
* A version of xQueueSelectFromSet() that can be used from an ISR.
*/
QueueSetMemberHandle_t xQueueSelectFromSetFromISR( QueueSetHandle_t xQueueSet ) PRIVILEGED_FUNCTION;
/* Not public API functions. */
void vQueueWaitForMessageRestricted( QueueHandle_t xQueue, TickType_t xTicksToWait ) PRIVILEGED_FUNCTION;
BaseType_t xQueueGenericReset( QueueHandle_t xQueue, BaseType_t xNewQueue ) PRIVILEGED_FUNCTION;
void vQueueSetQueueNumber( QueueHandle_t xQueue, UBaseType_t uxQueueNumber ) PRIVILEGED_FUNCTION;
UBaseType_t uxQueueGetQueueNumber( QueueHandle_t xQueue ) PRIVILEGED_FUNCTION;
uint8_t ucQueueGetQueueType( QueueHandle_t xQueue ) PRIVILEGED_FUNCTION;
#ifdef __cplusplus
}
#endif
#endif /* QUEUE_H */