Contiki 2.6

timer.h

Go to the documentation of this file.
00001 /** \addtogroup sys
00002  * @{ */
00003 
00004 /**
00005  * \defgroup timer Timer library
00006  *
00007  * The Contiki kernel does not provide support for timed
00008  * events. Rather, an application that wants to use timers needs to
00009  * explicitly use the timer library.
00010  *
00011  * The timer library provides functions for setting, resetting and
00012  * restarting timers, and for checking if a timer has expired. An
00013  * application must "manually" check if its timers have expired; this
00014  * is not done automatically.
00015  *
00016  * A timer is declared as a \c struct \c timer and all access to the
00017  * timer is made by a pointer to the declared timer.
00018  *
00019  * \note The timer library is not able to post events when a timer
00020  * expires. The \ref etimer "Event timers" should be used for this
00021  * purpose.
00022  *
00023  * \note The timer library uses the \ref clock "Clock library" to
00024  * measure time. Intervals should be specified in the format used by
00025  * the clock library.
00026  *
00027  * \sa \ref etimer "Event timers"
00028  *
00029  * @{
00030  */
00031 
00032 
00033 /**
00034  * \file
00035  * Timer library header file.
00036  * \author
00037  * Adam Dunkels <adam@sics.se>
00038  */
00039 
00040 /*
00041  * Copyright (c) 2004, Swedish Institute of Computer Science.
00042  * All rights reserved.
00043  *
00044  * Redistribution and use in source and binary forms, with or without
00045  * modification, are permitted provided that the following conditions
00046  * are met:
00047  * 1. Redistributions of source code must retain the above copyright
00048  *    notice, this list of conditions and the following disclaimer.
00049  * 2. Redistributions in binary form must reproduce the above copyright
00050  *    notice, this list of conditions and the following disclaimer in the
00051  *    documentation and/or other materials provided with the distribution.
00052  * 3. Neither the name of the Institute nor the names of its contributors
00053  *    may be used to endorse or promote products derived from this software
00054  *    without specific prior written permission.
00055  *
00056  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
00057  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
00058  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
00059  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
00060  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
00061  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
00062  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
00063  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
00064  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
00065  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
00066  * SUCH DAMAGE.
00067  *
00068  * This file is part of the Contiki operating system.
00069  *
00070  * Author: Adam Dunkels <adam@sics.se>
00071  *
00072  * $Id: timer.h,v 1.2 2008/09/21 08:58:05 adamdunkels Exp $
00073  */
00074 #ifndef __TIMER_H__
00075 #define __TIMER_H__
00076 
00077 #include "sys/clock.h"
00078 
00079 /**
00080  * A timer.
00081  *
00082  * This structure is used for declaring a timer. The timer must be set
00083  * with timer_set() before it can be used.
00084  *
00085  * \hideinitializer
00086  */
00087 struct timer {
00088   clock_time_t start;
00089   clock_time_t interval;
00090 };
00091 
00092 void timer_set(struct timer *t, clock_time_t interval);
00093 void timer_reset(struct timer *t);
00094 void timer_restart(struct timer *t);
00095 int timer_expired(struct timer *t);
00096 clock_time_t timer_remaining(struct timer *t);
00097 
00098 
00099 #endif /* __TIMER_H__ */
00100 
00101 /** @} */
00102 /** @} */