Seconds timer library
[Contiki system]

The stimer library provides functions for setting, resetting and restarting timers, and for checking if a timer has expired. More...

Data Structures
struct	stimer
	A timer. More...
Files
file	stimer.c
	Timer of seconds library implementation.
file	stimer.h
	Second timer library header file.
Functions
void	stimer_set (struct stimer *t, unsigned long interval)
	Set a timer.
void	stimer_reset (struct stimer *t)
	Reset the timer with the same interval.
void	stimer_restart (struct stimer *t)
	Restart the timer from the current point in time.
int	stimer_expired (struct stimer *t)
	Check if a timer has expired.
unsigned long	stimer_remaining (struct stimer *t)
	The time until the timer expires.
unsigned long	stimer_elapsed (struct stimer *t)
	The time elapsed since the timer started.

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Detailed Description

The stimer library provides functions for setting, resetting and restarting timers, and for checking if a timer has expired.

An application must "manually" check if its timers have expired; this is not done automatically.

A timer is declared as a struct stimer and all access to the timer is made by a pointer to the declared timer.

Note:

The stimer library is not able to post events when a timer expires. The Event timers should be used for this purpose.

The stimer library uses the Clock library to measure time. Intervals should be specified in the seconds.

See also:

Event timers

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Function Documentation

unsigned long stimer_elapsed

(

struct stimer *

t

)

The time elapsed since the timer started.

This function returns the time elapsed.

Parameters:

t

A pointer to the timer

Returns:

The time elapsed since the last start of the timer

int stimer_expired

(

struct stimer *

t

)

Check if a timer has expired.

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

Parameters:

t

A pointer to the timer

Returns:

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

unsigned long stimer_remaining

(

struct stimer *

t

)

The time until the timer expires.

This function returns the time until the timer expires.

Parameters:

t

A pointer to the timer

Returns:

The time until the timer expires

Referenced by uip_nd6_ra_input().

void stimer_reset

(

struct stimer *

t

)

Reset the timer with the same interval.

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

Parameters:

t

A pointer to the timer.

See also:

stimer_restart()

void stimer_restart

(

struct stimer *

t

)

Restart the timer from the current point in time.

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

Note:

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

Parameters:

t

A pointer to the timer.

See also:

stimer_reset()

void stimer_set	(	struct stimer *	t,
		unsigned long	interval
	)

Set a timer.

This function is used to set a timer for a time sometime in the future. The function stimer_expired() will evaluate to true after the timer has expired.

Parameters:

	t	A pointer to the timer
	interval	The interval before the timer expires.

Referenced by uip_nd6_na_input(), and uip_nd6_ra_input().