cpp_freertos::Thread Class Reference

#include <thread.hpp>

Inheritance diagram for cpp_freertos::Thread:

Public Member Functions
	Thread (const char *Name, uint16_t StackDepth, UBaseType_t Priority)
	Thread (const std::string Name, uint16_t StackDepth, UBaseType_t Priority)
	Thread (uint16_t StackDepth, UBaseType_t Priority)
virtual	~Thread ()
TaskHandle_t	GetHandle ()
std::string	GetName ()
char *	GetName ()
UBaseType_t	GetPriority ()
UBaseType_t	GetPriorityFromISR ()
void	Resume ()
void	ResumeFromISR ()
void	SetPriority (UBaseType_t NewPriority)
bool	Start ()
bool	Start (int core)
	Starts the task on the indicated core. More...
void	Suspend ()

Static Public Member Functions
static void	EndScheduler ()
static void	StartScheduler ()
static void	Yield ()

Protected Member Functions
virtual void	Cleanup ()
void	Delay (const TickType_t Delay)
void	DelayUntil (const TickType_t Period)
void	ResetDelayUntil ()
virtual void	Run ()=0
bool	Wait (ConditionVariable &Cv, Mutex &CvLock, TickType_t Timeout=portMAX_DELAY)

Friends
class	ConditionVariable

Detailed Description

Wrapper class around FreeRTOS's implementation of a task.

This is an abstract base class. To use this, you need to subclass it. All of your threads should be derived from the Thread class. Then implement the virtual Run function. This is a similar design to Java threading.

By default, we leverage C++ strings for the Thread Name. If this is not desirable, define CPP_FREERTOS_NO_CPP_STRINGS and the class will fall back to C character arrays.

Constructor & Destructor Documentation

Thread() [1/2]

Thread::Thread	(	const std::string	Name,
		uint16_t	StackDepth,
		UBaseType_t	Priority
	)

Constructor to create a named thread.

Parameters

Name	Name of the thread. Only useful for debugging.
StackDepth	Number of "words" allocated for the Thread stack.
Priority	FreeRTOS priority of this Thread.

Thread() [2/2]

Thread::Thread	(	uint16_t	StackDepth,
		UBaseType_t	Priority
	)

Constructor to create an unnamed thread.

Parameters

StackDepth	Number of "words" allocated for the Thread stack.
Priority	FreeRTOS priority of this Thread.

~Thread()

Thread::~Thread ( )

virtual

Our destructor. This must exist even if FreeRTOS is configured to disallow task deletion.

Member Function Documentation

Cleanup()

void Thread::Cleanup ( )

protectedvirtual

Called on exit from your Run() routine.

It is optional whether you implement this or not.

If you allow your Thread to exit its Run method, implementing a Cleanup method allows you to call your Thread's destructor. If you decide to call delete in your Cleanup function, be aware that additional derived classes shouldn't call delete.

Delay()

void cpp_freertos::Thread::Delay ( const TickType_t  Delay )

inlineprotected

If we can't delete a task, it makes no sense to have a Cleanup routine. Delay this thread for at least Delay ticks.

Parameters

Delay

How long to delay the thread.

DelayUntil()

void Thread::DelayUntil ( const TickType_t  Period )

protected

Delay this thread for Period ticks, taking into account the execution time of the thread.

This FreeRTOS permutation of delay can be used by periodic tasks to ensure a constant execution frequency.

Parameters

Period

How long to delay the thread.

EndScheduler()

static void cpp_freertos::Thread::EndScheduler ( )

inlinestatic

End the scheduler.

Note

Please see the FreeRTOS documentation regarding constraints with the implementation of this.

You need to use this call. Do NOT directly call vTaskEndScheduler while using this library.

GetHandle()

TaskHandle_t cpp_freertos::Thread::GetHandle ( )

inline

Accessor to get the thread's backing task handle. There is no setter, on purpose.

Returns

FreeRTOS task handle.

GetName()

std::string cpp_freertos::Thread::GetName ( )

inline

Get the name of this thread.

Returns

a C++ string with the name of the task.

GetPriority()

UBaseType_t cpp_freertos::Thread::GetPriority ( )

inline

Get the priority of this Thread.

Returns

Priority at the time this was called.

GetPriorityFromISR()

UBaseType_t cpp_freertos::Thread::GetPriorityFromISR ( )

inline

Get the priority of this Thread from ISR context.

Returns

Priority at the time this was called.

ResetDelayUntil()

void Thread::ResetDelayUntil ( )

protected

If you need to adjust or reset the period of the DelayUntil method.

Resume()

void cpp_freertos::Thread::Resume ( )

inline

Resume a specific thread.

ResumeFromISR()

void cpp_freertos::Thread::ResumeFromISR ( )

inline

Resume a specific thread from ISR context.

Run()

virtual void cpp_freertos::Thread::Run ( )

protectedpure virtual

Implementation of your actual thread code. You must override this function.

Note

If INCLUDE_vTaskDelete is defined, then you may return from your Run method. This will cause the task to be deleted from FreeRTOS, however you are still responsible to delete the task object. If this is not defined, then retuning from your Run() method will result in an assert.

Implemented in cpp_freertos::Task.

SetPriority()

void cpp_freertos::Thread::SetPriority ( UBaseType_t  NewPriority )

inline

Set the priority of this thread.

Parameters

NewPriority

The thread's new priority.

Start() [1/2]

bool Thread::Start

(

)

Starts a thread.

This is the API call that actually starts the thread running. It creates a backing FreeRTOS task. By separating object creation from starting the Thread, it solves the pure virtual fuction call failure case. If we attempt to automatically call xTaskCreate from the base class constructor, in certain conditions the task starts to run "before" the derived class is constructed! So we don't do that anymore.

This may be called from your ctor once you have completed your objects construction (so as the last step).

This should only be called once ever!

Start() [2/2]

bool Thread::Start

(

int

core

)

Starts the task on the indicated core.

Parameters

core

Returns

true if it could be started successfully

StartScheduler()

static void cpp_freertos::Thread::StartScheduler ( )

inlinestatic

Start the scheduler.

Note

You need to use this call. Do NOT directly call vTaskStartScheduler while using this library.

Suspend()

void cpp_freertos::Thread::Suspend ( )

inline

Suspend this thread.

Note

While a Thread can Suspend() itself, it cannot Resume() itself, becauseit's suspended.

Wait()

bool Thread::Wait ( ConditionVariable &  Cv, Mutex &  CvLock, TickType_t  Timeout = portMAX_DELAY  )

protected

Have this thread wait on a condition variable.

Note

Threads wait, while ConditionVariables signal.

Parameters

Cv	The condition variable associated with the Wait.
CvLock	The required condition variable lock. The Lock must be held before calling Wait.
Timeout	Allows you to specify a timeout on the Wait, if desired.

Returns

true if the condition variable was signaled, false if it timed out.

Yield()

static void cpp_freertos::Thread::Yield ( )

inlinestatic

Yield the scheduler.

Friends And Related Function Documentation

ConditionVariable

friend class ConditionVariable

friend

The Thread class and the ConditionVariable class are interdependent. If we allow the ConditionVariable class to access the internals of the Thread class, we can reduce the public interface, which is a good thing.

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The documentation for this class was generated from the following files:

• src/thread.hpp
• src/freertos-addon/c++/cthread.cpp