Callback timer

Collaboration diagram for Callback timer:

Files
file	ctimer.c
file	ctimer.h

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

Detailed Description

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

Function Documentation

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.

Definition at line 97 of file ctimer.c.

References list_init(), and process_start().

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.

Definition at line 105 of file ctimer.c.

References etimer_set(), list_add(), list_remove(), PROCESS_CONTEXT_BEGIN, PROCESS_CONTEXT_END, and PROCESS_CURRENT.

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()

Definition at line 125 of file ctimer.c.

References etimer_reset(), list_add(), list_remove(), PROCESS_CONTEXT_BEGIN, and PROCESS_CONTEXT_END.

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()

Definition at line 138 of file ctimer.c.

References etimer_restart(), list_add(), list_remove(), PROCESS_CONTEXT_BEGIN, and PROCESS_CONTEXT_END.

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.

Definition at line 151 of file ctimer.c.

References etimer_stop(), and list_remove().

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.

Definition at line 163 of file ctimer.c.

References etimer_expired(), and list_head().