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Timer library

Timer library

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

Data Structures

struct  uip_timer
 A timer. More...

Files

file  uip_timer.c
 

Timer library implementation.


file  uip_timer.h
 

Timer library header file.


Functions

void uip_timer_set (struct uip_timer *t, clock_time_t interval)
 Set a timer.
void uip_timer_reset (struct uip_timer *t)
 Reset the timer with the same interval.
void uip_timer_restart (struct uip_timer *t)
 Restart the timer from the current point in time.
int uip_timer_expired (struct uip_timer *t)
 Check if a timer has expired.

Detailed Description

The timer 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 timer and all access to the timer is made by a pointer to the declared timer.

Note:
The timer library uses the Clock library to measure time. Intervals should be specified in the format used by the clock library.

Function Documentation

int uip_timer_expired ( struct uip_timer 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:
tA pointer to the timer
Returns:
Non-zero if the timer has expired, zero otherwise.

Definition at line 118 of file uip_timer.c.

void uip_timer_reset ( struct uip_timer t )

Reset the timer with the same interval.

This function resets the timer with the same interval that was given to the timer_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 timer_rester() function.

Parameters:
tA pointer to the timer.
See also:
timer_restart()

Definition at line 81 of file uip_timer.c.

void uip_timer_restart ( struct uip_timer t )

Restart the timer from the current point in time.

This function restarts a timer with the same interval that was given to the timer_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 timer_reset() function instead.
Parameters:
tA pointer to the timer.
See also:
timer_reset()

Definition at line 101 of file uip_timer.c.

void uip_timer_set ( struct uip_timer t,
clock_time_t  interval 
)

Set a timer.

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

Parameters:
tA pointer to the timer
intervalThe interval before the timer expires.

Definition at line 61 of file uip_timer.c.