task.h

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    ***************************************************************************
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    ***************************************************************************

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    ***************************************************************************
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*/


#ifndef INC_TASK_H
#define INC_TASK_H

#ifndef INC_FREERTOS_H
    #error "include FreeRTOS.h must appear in source files before include task.h"
#endif

#include "list.h"

#ifdef __cplusplus
extern "C" {
#endif

/*-----------------------------------------------------------
 * MACROS AND DEFINITIONS
 *----------------------------------------------------------*/

#define tskKERNEL_VERSION_NUMBER "V9.0.0rc2"
#define tskKERNEL_VERSION_MAJOR 9
#define tskKERNEL_VERSION_MINOR 0
#define tskKERNEL_VERSION_BUILD 0

typedef void * TaskHandle_t;

/*
 * Defines the prototype to which the application task hook function must
 * conform.
 */
typedef BaseType_t (*TaskHookFunction_t)( void * );

/* Task states returned by eTaskGetState. */
typedef enum
{
    eRunning = 0,   /* A task is querying the state of itself, so must be running. */
    eReady,         /* The task being queried is in a read or pending ready list. */
    eBlocked,       /* The task being queried is in the Blocked state. */
    eSuspended,     /* The task being queried is in the Suspended state, or is in the Blocked state with an infinite time out. */
    eDeleted,       /* The task being queried has been deleted, but its TCB has not yet been freed. */
    eInvalid            /* Used as an 'invalid state' value. */
} eTaskState;

/* Actions that can be performed when vTaskNotify() is called. */
typedef enum
{
    eNoAction = 0,              /* Notify the task without updating its notify value. */
    eSetBits,                   /* Set bits in the task's notification value. */
    eIncrement,                 /* Increment the task's notification value. */
    eSetValueWithOverwrite,     /* Set the task's notification value to a specific value even if the previous value has not yet been read by the task. */
    eSetValueWithoutOverwrite   /* Set the task's notification value if the previous value has been read by the task. */
} eNotifyAction;

/*
 * Used internally only.
 */
typedef struct xTIME_OUT
{
    BaseType_t xOverflowCount;
    TickType_t xTimeOnEntering;
} TimeOut_t;

/*
 * Defines the memory ranges allocated to the task when an MPU is used.
 */
typedef struct xMEMORY_REGION
{
    void *pvBaseAddress;
    uint32_t ulLengthInBytes;
    uint32_t ulParameters;
} MemoryRegion_t;

/*
 * Parameters required to create an MPU protected task.
 */
typedef struct xTASK_PARAMETERS
{
    TaskFunction_t pvTaskCode;
    const char * const pcName;  /*lint !e971 Unqualified char types are allowed for strings and single characters only. */
    uint16_t usStackDepth;
    void *pvParameters;
    UBaseType_t uxPriority;
    StackType_t *puxStackBuffer;
    MemoryRegion_t xRegions[ portNUM_CONFIGURABLE_REGIONS ];
} TaskParameters_t;

/* Used with the uxTaskGetSystemState() function to return the state of each task
in the system. */
typedef struct xTASK_STATUS
{
    TaskHandle_t xHandle;           /* The handle of the task to which the rest of the information in the structure relates. */
    const char *pcTaskName;         /* A pointer to the task's name.  This value will be invalid if the task was deleted since the structure was populated! */ /*lint !e971 Unqualified char types are allowed for strings and single characters only. */
    UBaseType_t xTaskNumber;        /* A number unique to the task. */
    eTaskState eCurrentState;       /* The state in which the task existed when the structure was populated. */
    UBaseType_t uxCurrentPriority;  /* The priority at which the task was running (may be inherited) when the structure was populated. */
    UBaseType_t uxBasePriority;     /* The priority to which the task will return if the task's current priority has been inherited to avoid unbounded priority inversion when obtaining a mutex.  Only valid if configUSE_MUTEXES is defined as 1 in FreeRTOSConfig.h. */
    uint32_t ulRunTimeCounter;      /* The total run time allocated to the task so far, as defined by the run time stats clock.  See http://www.freertos.org/rtos-run-time-stats.html.  Only valid when configGENERATE_RUN_TIME_STATS is defined as 1 in FreeRTOSConfig.h. */
    StackType_t *pxStackBase;       /* Points to the lowest address of the task's stack area. */
    uint16_t usStackHighWaterMark;  /* The minimum amount of stack space that has remained for the task since the task was created.  The closer this value is to zero the closer the task has come to overflowing its stack. */
} TaskStatus_t;

/* Possible return values for eTaskConfirmSleepModeStatus(). */
typedef enum
{
    eAbortSleep = 0,        /* A task has been made ready or a context switch pended since portSUPPORESS_TICKS_AND_SLEEP() was called - abort entering a sleep mode. */
    eStandardSleep,         /* Enter a sleep mode that will not last any longer than the expected idle time. */
    eNoTasksWaitingTimeout  /* No tasks are waiting for a timeout so it is safe to enter a sleep mode that can only be exited by an external interrupt. */
} eSleepModeStatus;

#define tskIDLE_PRIORITY            ( ( UBaseType_t ) 0U )

#define taskYIELD()                 portYIELD()

#define taskENTER_CRITICAL()        portENTER_CRITICAL()
#define taskENTER_CRITICAL_FROM_ISR() portSET_INTERRUPT_MASK_FROM_ISR()

#define taskEXIT_CRITICAL()         portEXIT_CRITICAL()
#define taskEXIT_CRITICAL_FROM_ISR( x ) portCLEAR_INTERRUPT_MASK_FROM_ISR( x )

#define taskDISABLE_INTERRUPTS()    portDISABLE_INTERRUPTS()

#define taskENABLE_INTERRUPTS()     portENABLE_INTERRUPTS()

/* Definitions returned by xTaskGetSchedulerState().  taskSCHEDULER_SUSPENDED is
0 to generate more optimal code when configASSERT() is defined as the constant
is used in assert() statements. */
#define taskSCHEDULER_SUSPENDED     ( ( BaseType_t ) 0 )
#define taskSCHEDULER_NOT_STARTED   ( ( BaseType_t ) 1 )
#define taskSCHEDULER_RUNNING       ( ( BaseType_t ) 2 )


/*-----------------------------------------------------------
 * TASK CREATION API
 *----------------------------------------------------------*/

#if( configSUPPORT_DYNAMIC_ALLOCATION == 1 )
    BaseType_t xTaskCreate( TaskFunction_t pxTaskCode, const char * const pcName, const uint16_t usStackDepth, void * const pvParameters, UBaseType_t uxPriority, TaskHandle_t * const pxCreatedTask ) PRIVILEGED_FUNCTION; /*lint !e971 Unqualified char types are allowed for strings and single characters only. */
#endif

#if( configSUPPORT_STATIC_ALLOCATION == 1 )
    TaskHandle_t xTaskCreateStatic( TaskFunction_t pxTaskCode, const char * const pcName, const uint32_t ulStackDepth, void * const pvParameters, UBaseType_t uxPriority, StackType_t * const puxStackBuffer, StaticTask_t * const pxTaskBuffer ) PRIVILEGED_FUNCTION; /*lint !e971 Unqualified char types are allowed for strings and single characters only. */
#endif /* configSUPPORT_STATIC_ALLOCATION */

#define xTaskCreateRestricted( x, pxCreatedTask ) xTaskGenericCreate( ((x)->pvTaskCode), ((x)->pcName), ((x)->usStackDepth), ((x)->pvParameters), ((x)->uxPriority), (pxCreatedTask), ((x)->puxStackBuffer), ( NULL ), ((x)->xRegions) )

void vTaskAllocateMPURegions( TaskHandle_t xTask, const MemoryRegion_t * const pxRegions ) PRIVILEGED_FUNCTION;

void vTaskDelete( TaskHandle_t xTaskToDelete ) PRIVILEGED_FUNCTION;

/*-----------------------------------------------------------
 * TASK CONTROL API
 *----------------------------------------------------------*/

void vTaskDelay( const TickType_t xTicksToDelay ) PRIVILEGED_FUNCTION;

void vTaskDelayUntil( TickType_t * const pxPreviousWakeTime, const TickType_t xTimeIncrement ) PRIVILEGED_FUNCTION;

BaseType_t xTaskAbortDelay( TaskHandle_t xTask ) PRIVILEGED_FUNCTION;

UBaseType_t uxTaskPriorityGet( TaskHandle_t xTask ) PRIVILEGED_FUNCTION;

UBaseType_t uxTaskPriorityGetFromISR( TaskHandle_t xTask ) PRIVILEGED_FUNCTION;

eTaskState eTaskGetState( TaskHandle_t xTask ) PRIVILEGED_FUNCTION;

void vTaskGetTaskInfo( TaskHandle_t xTask, TaskStatus_t *pxTaskStatus, BaseType_t xGetFreeStackSpace, eTaskState eState ) PRIVILEGED_FUNCTION;

void vTaskPrioritySet( TaskHandle_t xTask, UBaseType_t uxNewPriority ) PRIVILEGED_FUNCTION;

void vTaskSuspend( TaskHandle_t xTaskToSuspend ) PRIVILEGED_FUNCTION;

void vTaskResume( TaskHandle_t xTaskToResume ) PRIVILEGED_FUNCTION;

BaseType_t xTaskResumeFromISR( TaskHandle_t xTaskToResume ) PRIVILEGED_FUNCTION;

/*-----------------------------------------------------------
 * SCHEDULER CONTROL
 *----------------------------------------------------------*/

void vTaskStartScheduler( void ) PRIVILEGED_FUNCTION;

void vTaskEndScheduler( void ) PRIVILEGED_FUNCTION;

void vTaskSuspendAll( void ) PRIVILEGED_FUNCTION;

BaseType_t xTaskResumeAll( void ) PRIVILEGED_FUNCTION;

/*-----------------------------------------------------------
 * TASK UTILITIES
 *----------------------------------------------------------*/

TickType_t xTaskGetTickCount( void ) PRIVILEGED_FUNCTION;

TickType_t xTaskGetTickCountFromISR( void ) PRIVILEGED_FUNCTION;

UBaseType_t uxTaskGetNumberOfTasks( void ) PRIVILEGED_FUNCTION;

char *pcTaskGetName( TaskHandle_t xTaskToQuery ) PRIVILEGED_FUNCTION; /*lint !e971 Unqualified char types are allowed for strings and single characters only. */

TaskHandle_t xTaskGetTaskHandle( const char *pcNameToQuery ) PRIVILEGED_FUNCTION; /*lint !e971 Unqualified char types are allowed for strings and single characters only. */

UBaseType_t uxTaskGetStackHighWaterMark( TaskHandle_t xTask ) PRIVILEGED_FUNCTION;

/* When using trace macros it is sometimes necessary to include task.h before
FreeRTOS.h.  When this is done TaskHookFunction_t will not yet have been defined,
so the following two prototypes will cause a compilation error.  This can be
fixed by simply guarding against the inclusion of these two prototypes unless
they are explicitly required by the configUSE_APPLICATION_TASK_TAG configuration
constant. */
#ifdef configUSE_APPLICATION_TASK_TAG
    #if configUSE_APPLICATION_TASK_TAG == 1

        void vTaskSetApplicationTaskTag( TaskHandle_t xTask, TaskHookFunction_t pxHookFunction ) PRIVILEGED_FUNCTION;

        TaskHookFunction_t xTaskGetApplicationTaskTag( TaskHandle_t xTask ) PRIVILEGED_FUNCTION;
    #endif /* configUSE_APPLICATION_TASK_TAG ==1 */
#endif /* ifdef configUSE_APPLICATION_TASK_TAG */

#if( configNUM_THREAD_LOCAL_STORAGE_POINTERS > 0 )

    /* Each task contains an array of pointers that is dimensioned by the
    configNUM_THREAD_LOCAL_STORAGE_POINTERS setting in FreeRTOSConfig.h.  The
    kernel does not use the pointers itself, so the application writer can use
    the pointers for any purpose they wish.  The following two functions are
    used to set and query a pointer respectively. */
    void vTaskSetThreadLocalStoragePointer( TaskHandle_t xTaskToSet, BaseType_t xIndex, void *pvValue ) PRIVILEGED_FUNCTION;
    void *pvTaskGetThreadLocalStoragePointer( TaskHandle_t xTaskToQuery, BaseType_t xIndex ) PRIVILEGED_FUNCTION;

#endif

BaseType_t xTaskCallApplicationTaskHook( TaskHandle_t xTask, void *pvParameter ) PRIVILEGED_FUNCTION;

TaskHandle_t xTaskGetIdleTaskHandle( void ) PRIVILEGED_FUNCTION;

UBaseType_t uxTaskGetSystemState( TaskStatus_t * const pxTaskStatusArray, const UBaseType_t uxArraySize, uint32_t * const pulTotalRunTime ) PRIVILEGED_FUNCTION;

void vTaskList( char * pcWriteBuffer ) PRIVILEGED_FUNCTION; /*lint !e971 Unqualified char types are allowed for strings and single characters only. */

void vTaskGetRunTimeStats( char *pcWriteBuffer ) PRIVILEGED_FUNCTION; /*lint !e971 Unqualified char types are allowed for strings and single characters only. */

BaseType_t xTaskGenericNotify( TaskHandle_t xTaskToNotify, uint32_t ulValue, eNotifyAction eAction, uint32_t *pulPreviousNotificationValue ) PRIVILEGED_FUNCTION;
#define xTaskNotify( xTaskToNotify, ulValue, eAction ) xTaskGenericNotify( ( xTaskToNotify ), ( ulValue ), ( eAction ), NULL )
#define xTaskNotifyAndQuery( xTaskToNotify, ulValue, eAction, pulPreviousNotifyValue ) xTaskGenericNotify( ( xTaskToNotify ), ( ulValue ), ( eAction ), ( pulPreviousNotifyValue ) )

BaseType_t xTaskGenericNotifyFromISR( TaskHandle_t xTaskToNotify, uint32_t ulValue, eNotifyAction eAction, uint32_t *pulPreviousNotificationValue, BaseType_t *pxHigherPriorityTaskWoken ) PRIVILEGED_FUNCTION;
#define xTaskNotifyFromISR( xTaskToNotify, ulValue, eAction, pxHigherPriorityTaskWoken ) xTaskGenericNotifyFromISR( ( xTaskToNotify ), ( ulValue ), ( eAction ), NULL, ( pxHigherPriorityTaskWoken ) )
#define xTaskNotifyAndQueryFromISR( xTaskToNotify, ulValue, eAction, pulPreviousNotificationValue, pxHigherPriorityTaskWoken ) xTaskGenericNotifyFromISR( ( xTaskToNotify ), ( ulValue ), ( eAction ), ( pulPreviousNotificationValue ), ( pxHigherPriorityTaskWoken ) )

BaseType_t xTaskNotifyWait( uint32_t ulBitsToClearOnEntry, uint32_t ulBitsToClearOnExit, uint32_t *pulNotificationValue, TickType_t xTicksToWait ) PRIVILEGED_FUNCTION;

#define xTaskNotifyGive( xTaskToNotify ) xTaskGenericNotify( ( xTaskToNotify ), ( 0 ), eIncrement, NULL )

void vTaskNotifyGiveFromISR( TaskHandle_t xTaskToNotify, BaseType_t *pxHigherPriorityTaskWoken ) PRIVILEGED_FUNCTION;

uint32_t ulTaskNotifyTake( BaseType_t xClearCountOnExit, TickType_t xTicksToWait ) PRIVILEGED_FUNCTION;

BaseType_t xTaskNotifyStateClear( TaskHandle_t xTask );

/*-----------------------------------------------------------
 * SCHEDULER INTERNALS AVAILABLE FOR PORTING PURPOSES
 *----------------------------------------------------------*/

/*
 * THIS FUNCTION MUST NOT BE USED FROM APPLICATION CODE.  IT IS ONLY
 * INTENDED FOR USE WHEN IMPLEMENTING A PORT OF THE SCHEDULER AND IS
 * AN INTERFACE WHICH IS FOR THE EXCLUSIVE USE OF THE SCHEDULER.
 *
 * Called from the real time kernel tick (either preemptive or cooperative),
 * this increments the tick count and checks if any tasks that are blocked
 * for a finite period required removing from a blocked list and placing on
 * a ready list.  If a non-zero value is returned then a context switch is
 * required because either:
 *   + A task was removed from a blocked list because its timeout had expired,
 *     or
 *   + Time slicing is in use and there is a task of equal priority to the
 *     currently running task.
 */
BaseType_t xTaskIncrementTick( void ) PRIVILEGED_FUNCTION;

/*
 * THIS FUNCTION MUST NOT BE USED FROM APPLICATION CODE.  IT IS AN
 * INTERFACE WHICH IS FOR THE EXCLUSIVE USE OF THE SCHEDULER.
 *
 * THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED.
 *
 * Removes the calling task from the ready list and places it both
 * on the list of tasks waiting for a particular event, and the
 * list of delayed tasks.  The task will be removed from both lists
 * and replaced on the ready list should either the event occur (and
 * there be no higher priority tasks waiting on the same event) or
 * the delay period expires.
 *
 * The 'unordered' version replaces the event list item value with the
 * xItemValue value, and inserts the list item at the end of the list.
 *
 * The 'ordered' version uses the existing event list item value (which is the
 * owning tasks priority) to insert the list item into the event list is task
 * priority order.
 *
 * @param pxEventList The list containing tasks that are blocked waiting
 * for the event to occur.
 *
 * @param xItemValue The item value to use for the event list item when the
 * event list is not ordered by task priority.
 *
 * @param xTicksToWait The maximum amount of time that the task should wait
 * for the event to occur.  This is specified in kernel ticks,the constant
 * portTICK_PERIOD_MS can be used to convert kernel ticks into a real time
 * period.
 */
void vTaskPlaceOnEventList( List_t * const pxEventList, const TickType_t xTicksToWait ) PRIVILEGED_FUNCTION;
void vTaskPlaceOnUnorderedEventList( List_t * pxEventList, const TickType_t xItemValue, const TickType_t xTicksToWait ) PRIVILEGED_FUNCTION;

/*
 * THIS FUNCTION MUST NOT BE USED FROM APPLICATION CODE.  IT IS AN
 * INTERFACE WHICH IS FOR THE EXCLUSIVE USE OF THE SCHEDULER.
 *
 * THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED.
 *
 * This function performs nearly the same function as vTaskPlaceOnEventList().
 * The difference being that this function does not permit tasks to block
 * indefinitely, whereas vTaskPlaceOnEventList() does.
 *
 */
void vTaskPlaceOnEventListRestricted( List_t * const pxEventList, TickType_t xTicksToWait, const BaseType_t xWaitIndefinitely ) PRIVILEGED_FUNCTION;

/*
 * THIS FUNCTION MUST NOT BE USED FROM APPLICATION CODE.  IT IS AN
 * INTERFACE WHICH IS FOR THE EXCLUSIVE USE OF THE SCHEDULER.
 *
 * THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED.
 *
 * Removes a task from both the specified event list and the list of blocked
 * tasks, and places it on a ready queue.
 *
 * xTaskRemoveFromEventList()/xTaskRemoveFromUnorderedEventList() will be called
 * if either an event occurs to unblock a task, or the block timeout period
 * expires.
 *
 * xTaskRemoveFromEventList() is used when the event list is in task priority
 * order.  It removes the list item from the head of the event list as that will
 * have the highest priority owning task of all the tasks on the event list.
 * xTaskRemoveFromUnorderedEventList() is used when the event list is not
 * ordered and the event list items hold something other than the owning tasks
 * priority.  In this case the event list item value is updated to the value
 * passed in the xItemValue parameter.
 *
 * @return pdTRUE if the task being removed has a higher priority than the task
 * making the call, otherwise pdFALSE.
 */
BaseType_t xTaskRemoveFromEventList( const List_t * const pxEventList ) PRIVILEGED_FUNCTION;
BaseType_t xTaskRemoveFromUnorderedEventList( ListItem_t * pxEventListItem, const TickType_t xItemValue ) PRIVILEGED_FUNCTION;

/*
 * THIS FUNCTION MUST NOT BE USED FROM APPLICATION CODE.  IT IS ONLY
 * INTENDED FOR USE WHEN IMPLEMENTING A PORT OF THE SCHEDULER AND IS
 * AN INTERFACE WHICH IS FOR THE EXCLUSIVE USE OF THE SCHEDULER.
 *
 * Sets the pointer to the current TCB to the TCB of the highest priority task
 * that is ready to run.
 */
void vTaskSwitchContext( void ) PRIVILEGED_FUNCTION;

/*
 * THESE FUNCTIONS MUST NOT BE USED FROM APPLICATION CODE.  THEY ARE USED BY
 * THE EVENT BITS MODULE.
 */
TickType_t uxTaskResetEventItemValue( void ) PRIVILEGED_FUNCTION;

/*
 * Return the handle of the calling task.
 */
TaskHandle_t xTaskGetCurrentTaskHandle( void ) PRIVILEGED_FUNCTION;

/*
 * Capture the current time status for future reference.
 */
void vTaskSetTimeOutState( TimeOut_t * const pxTimeOut ) PRIVILEGED_FUNCTION;

/*
 * Compare the time status now with that previously captured to see if the
 * timeout has expired.
 */
BaseType_t xTaskCheckForTimeOut( TimeOut_t * const pxTimeOut, TickType_t * const pxTicksToWait ) PRIVILEGED_FUNCTION;

/*
 * Shortcut used by the queue implementation to prevent unnecessary call to
 * taskYIELD();
 */
void vTaskMissedYield( void ) PRIVILEGED_FUNCTION;

/*
 * Returns the scheduler state as taskSCHEDULER_RUNNING,
 * taskSCHEDULER_NOT_STARTED or taskSCHEDULER_SUSPENDED.
 */
BaseType_t xTaskGetSchedulerState( void ) PRIVILEGED_FUNCTION;

/*
 * Raises the priority of the mutex holder to that of the calling task should
 * the mutex holder have a priority less than the calling task.
 */
void vTaskPriorityInherit( TaskHandle_t const pxMutexHolder ) PRIVILEGED_FUNCTION;

/*
 * Set the priority of a task back to its proper priority in the case that it
 * inherited a higher priority while it was holding a semaphore.
 */
BaseType_t xTaskPriorityDisinherit( TaskHandle_t const pxMutexHolder ) PRIVILEGED_FUNCTION;

/*
 * Get the uxTCBNumber assigned to the task referenced by the xTask parameter.
 */
UBaseType_t uxTaskGetTaskNumber( TaskHandle_t xTask ) PRIVILEGED_FUNCTION;

/*
 * Set the uxTaskNumber of the task referenced by the xTask parameter to
 * uxHandle.
 */
void vTaskSetTaskNumber( TaskHandle_t xTask, const UBaseType_t uxHandle ) PRIVILEGED_FUNCTION;

/*
 * Only available when configUSE_TICKLESS_IDLE is set to 1.
 * If tickless mode is being used, or a low power mode is implemented, then
 * the tick interrupt will not execute during idle periods.  When this is the
 * case, the tick count value maintained by the scheduler needs to be kept up
 * to date with the actual execution time by being skipped forward by a time
 * equal to the idle period.
 */
void vTaskStepTick( const TickType_t xTicksToJump ) PRIVILEGED_FUNCTION;

/*
 * Only avilable when configUSE_TICKLESS_IDLE is set to 1.
 * Provided for use within portSUPPRESS_TICKS_AND_SLEEP() to allow the port
 * specific sleep function to determine if it is ok to proceed with the sleep,
 * and if it is ok to proceed, if it is ok to sleep indefinitely.
 *
 * This function is necessary because portSUPPRESS_TICKS_AND_SLEEP() is only
 * called with the scheduler suspended, not from within a critical section.  It
 * is therefore possible for an interrupt to request a context switch between
 * portSUPPRESS_TICKS_AND_SLEEP() and the low power mode actually being
 * entered.  eTaskConfirmSleepModeStatus() should be called from a short
 * critical section between the timer being stopped and the sleep mode being
 * entered to ensure it is ok to proceed into the sleep mode.
 */
eSleepModeStatus eTaskConfirmSleepModeStatus( void ) PRIVILEGED_FUNCTION;

/*
 * For internal use only.  Increment the mutex held count when a mutex is
 * taken and return the handle of the task that has taken the mutex.
 */
void *pvTaskIncrementMutexHeldCount( void ) PRIVILEGED_FUNCTION;

#ifdef __cplusplus
}
#endif
#endif /* INC_TASK_H */