Callback timer
[Contiki system]

The ctimer module provides a timer mechanism that calls a specified C function when a ctimer expires. More...

Files
file	ctimer.c
	Callback timer implementation.
file	ctimer.h
	Header file for the callback timer.
Functions
void	ctimer_init (void)
	Initialize the callback timer library.
void	ctimer_set (struct ctimer *c, clock_time_t t, void(*f)(void *), void *ptr)
	Set a callback timer.
void	ctimer_reset (struct ctimer *c)
	Reset a callback timer with the same interval as was previously set.
void	ctimer_restart (struct ctimer *c)
	Restart a callback timer from the current point in time.
void	ctimer_stop (struct ctimer *c)
	Stop a pending callback timer.
int	ctimer_expired (struct ctimer *c)
	Check if a callback timer has expired.

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Detailed Description

The ctimer module provides a timer mechanism that calls a specified C function when a ctimer expires.

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Function Documentation

int ctimer_expired

(

struct ctimer *

c

)

Check if a callback timer has expired.

Parameters:

c

A pointer to the callback timer

Returns:

Non-zero if the timer has expired, zero otherwise.

This function tests if a callback timer has expired and returns true or false depending on its status.

void ctimer_init

(

void

)

Initialize the callback timer library.

This function initializes the callback timer library and should be called from the system boot up code.

Referenced by main().

void ctimer_reset

(

struct ctimer *

c

)

Reset a callback timer with the same interval as was previously set.

Parameters:

c

A pointer to the callback timer.

This function resets the callback timer with the same interval that was given to the callback timer with the ctimer_set() function. The start point of the interval is the exact time that the callback timer last expired. Therefore, this function will cause the timer to be stable over time, unlike the ctimer_restart() function.

See also:

ctimer_restart()

void ctimer_restart

(

struct ctimer *

c

)

Restart a callback timer from the current point in time.

Parameters:

c

A pointer to the callback timer.

This function restarts the callback timer with the same interval that was given to the ctimer_set() function. The callback timer will start at the current time.

Note:

A periodic timer will drift if this function is used to reset it. For periodic timers, use the ctimer_reset() function instead.

See also:

ctimer_reset()

void ctimer_set	(	struct ctimer *	c,
		clock_time_t	t,
		void(*)(void *)	f,
		void *	ptr
	)

Set a callback timer.

Parameters:

	c	A pointer to the callback timer.
	t	The interval before the timer expires.
	f	A function to be called when the timer expires.
	ptr	An opaque pointer that will be supplied as an argument to the callback function.

This function is used to set a callback timer for a time sometime in the future. When the callback timer expires, the callback function f will be called with ptr as argument.

Examples:

example-multihop.c.

void ctimer_stop

(

struct ctimer *

c

)

Stop a pending callback timer.

Parameters:

c

A pointer to the pending callback timer.

This function stops a callback timer that has previously been set with ctimer_set(), ctimer_reset(), or ctimer_restart(). After this function has been called, the callback timer will be expired and will not call the callback function.