contiki/core/sys/timer.h

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/** \addtogroup sys
* @{ */
/**
* \defgroup timer Timer library
*
* The Contiki kernel does not provide support for timed
* events. Rather, an application that wants to use timers needs to
* explicitly use the timer library.
*
* 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 \c struct \c timer and all access to the
* timer is made by a pointer to the declared timer.
*
* \note The timer library is not able to post events when a timer
* expires. The \ref etimer "Event timers" should be used for this
* purpose.
*
* \note The timer library uses the \ref clock "Clock library" to
* measure time. Intervals should be specified in the format used by
* the clock library.
*
* \sa \ref etimer "Event timers"
*
* @{
*/
/**
* \file
* Timer library header file.
* \author
* Adam Dunkels <adam@sics.se>
*/
/*
* Copyright (c) 2004, Swedish Institute of Computer Science.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* This file is part of the Contiki operating system.
*
* Author: Adam Dunkels <adam@sics.se>
*
*/
#ifndef TIMER_H_
#define TIMER_H_
#include "sys/clock.h"
/**
* A timer.
*
* This structure is used for declaring a timer. The timer must be set
* with timer_set() before it can be used.
*
* \hideinitializer
*/
struct timer {
clock_time_t start;
clock_time_t interval;
};
CCIF void timer_set(struct timer *t, clock_time_t interval);
void timer_reset(struct timer *t);
void timer_restart(struct timer *t);
CCIF int timer_expired(struct timer *t);
clock_time_t timer_remaining(struct timer *t);
#endif /* TIMER_H_ */
/** @} */
/** @} */