Thread Management
[RT-Thread Kernel API]

Functions
rt_err_t	rt_thread_init (struct rt_thread *thread, const char *name, void(*entry)(void *parameter), void *parameter, void *stack_start, rt_uint32_t stack_size, rt_uint8_t priority, rt_uint32_t tick)
rt_err_t	rt_thread_detach (rt_thread_t thread)
rt_thread_t	rt_thread_create (const char *name, void(*entry)(void *parameter), void *parameter, rt_uint32_t stack_size, rt_uint8_t priority, rt_uint32_t tick)
rt_thread_t	rt_thread_self (void)
rt_err_t	rt_thread_startup (rt_thread_t thread)
rt_err_t	rt_thread_delete (rt_thread_t thread)
rt_err_t	rt_thread_yield (void)
rt_err_t	rt_thread_delay (rt_tick_t tick)
rt_err_t	rt_thread_suspend (rt_thread_t thread)
rt_err_t	rt_thread_resume (rt_thread_t thread)
void	rt_thread_timeout (void *parameter)
void	rt_thread_idle_init (void)
void	rt_thread_idle_sethook (void(*hook)())
void	rt_system_scheduler_init (void)
void	rt_system_scheduler_start (void)
void	rt_schedule (void)
void	rt_schedule_insert_thread (struct rt_thread *thread)
void	rt_schedule_remove_thread (struct rt_thread *thread)
void	rt_enter_critical (void)
void	rt_exit_critical (void)
rt_err_t	rt_thread_sleep (rt_tick_t tick)

---

Detailed Description

RT-Thread operating system supports multi-task systems, which are based on thread scheduling.

• The scheduling is a full preemptive priority-based scheduling algorithm.
• 256 priority levels are supported, in which 0 is the highest and 255 the lowest. The 255th priority is used for idle thread.
• Threads running at same priority level are supports. The shared time-slice round-robin scheduling is used for this case.
• The time of scheduler to determine the next highest ready thread is determinant.
• There are three status in thread management
  1. Runnning
  2. Ready
  3. Blocked
• The number of threads in the system is unlimited, only related with RAM.

---

Function Documentation

void rt_enter_critical

(

)

This function will lock the thread scheduler.

void rt_exit_critical

(

)

This function will unlock the thread scheduler.

void rt_schedule

(

)

This function will perform one schedule. It will select one thread with the highest priority level, then switch to it.

void rt_schedule_insert_thread

(

struct rt_thread *

thread

)

This function will insert a thread to system ready queue. The state of thread will be set as READY and remove from suspend queue.

Parameters:

thread

the thread to be inserted

Note:

Please do not invoke this function in user application.

void rt_schedule_remove_thread

(

struct rt_thread *

thread

)

This function will remove a thread from system ready queue.

Parameters:

thread

the thread to be removed

Note:

Please do not invoke this function in user application.

void rt_system_scheduler_init

(

void

)

This function will init the system scheduler

void rt_system_scheduler_start

(

void

)

This function will startup scheduler. It will select one thread with the highest priority level, then switch to it.

rt_thread_t rt_thread_create	(	const char *	name,
		void(*)(void *parameter)	entry,
		void *	parameter,
		rt_uint32_t	stack_size,
		rt_uint8_t	priority,
		rt_uint32_t	tick
	)

This function will create a thread object and allocate thread object memory and stack.

Parameters:

	name	the name of thread, which shall be unique
	entry	the entry function of thread
	parameter	the parameter of thread enter function
	stack_size	the size of thread stack
	priority	the priority of thread
	tick	the time slice if there are same priority thread

Returns:

the created thread object

rt_err_t rt_thread_delay

(

rt_tick_t

tick

)

This function will let current thread delay for some ticks.

Parameters:

tick

the delay ticks

Returns:

the operation status, RT_EOK on OK; RT_ERROR on error

rt_err_t rt_thread_delete

(

rt_thread_t

thread

)

This function will delete a thread. The thread object will be remove from thread queue and detached/deleted from system object management.

Parameters:

thread

the thread to be deleted

Returns:

the operation status, RT_EOK on OK; -RT_ERROR on error

rt_err_t rt_thread_detach

(

rt_thread_t

thread

)

This function will detach a thread. The thread object will be remove from thread queue and detached/deleted from system object management.

Parameters:

thread

the thread to be deleted

Returns:

the operation status, RT_EOK on OK; -RT_ERROR on error

void rt_thread_idle_init

(

)

This function will initialize idle thread, then start it.

Note:

this function must be invoked when system init.

void rt_thread_idle_sethook

(

void(*)()

hook

)

This function will set a hook function to idle thread loop.

Parameters:

hook

the specified hook function

Note:

the hook function must be simple and never be blocked or suspend.

rt_err_t rt_thread_init	(	struct rt_thread *	thread,
		const char *	name,
		void(*)(void *parameter)	entry,
		void *	parameter,
		void *	stack_start,
		rt_uint32_t	stack_size,
		rt_uint8_t	priority,
		rt_uint32_t	tick
	)

This function will init a thread, normally it's used to initialize a static thread object.

Parameters:

	thread	the static thread object
	name	the name of thread, which shall be unique
	entry	the entry function of thread
	parameter	the parameter of thread enter function
	stack_start	the start address of thread stack
	stack_size	the size of thread stack
	priority	the priority of thread
	tick	the time slice if there are same priority thread

Returns:

the operation status, RT_EOK on OK; -RT_ERROR on error

rt_err_t rt_thread_resume

(

rt_thread_t

thread

)

This function will resume a thread and put it to system ready queue.

Parameters:

thread

the thread to be resumed

Returns:

the operation status, RT_EOK on OK; -RT_ERROR on error

rt_thread_t rt_thread_self

(

void

)

This function will return self thread object

Returns:

the self thread object

rt_err_t rt_thread_sleep

(

rt_tick_t

tick

)

This function will let current thread sleep for some ticks.

Parameters:

tick

the sleep ticks

Returns:

the operation status, RT_EOK on OK; RT_ERROR on error

rt_err_t rt_thread_startup

(

rt_thread_t

thread

)

This function will start a thread and put it to system ready queue

Parameters:

thread

the thread to be started

Returns:

the operation status, RT_EOK on OK; -RT_ERROR on error

rt_err_t rt_thread_suspend

(

rt_thread_t

thread

)

This function will suspend the specified thread.

Parameters:

thread

the thread to be suspended

Returns:

the operation status, RT_EOK on OK; -RT_ERROR on error

void rt_thread_timeout

(

void *

parameter

)

This function is the timeout function for thread, normally which will be invoked when thread is timeout to wait some recourse.

Parameters:

parameter

the parameter of thread timeout function

rt_err_t rt_thread_yield

(

)

This function will let current thread yield processor, and scheduler will get a highest thread to run. After yield processor, the current thread is still in READY state.

Returns:

the operation status, RT_EOK on OK; -RT_ERROR on error