contiki/core/sys/ctimer.h

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/*
* Copyright (c) 2006, 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.
*
*/
/**
* \file
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* Header file for the callback timer
* \author
* Adam Dunkels <adam@sics.se>
*/
/**
* \addtogroup sys
* @{
*/
/**
* \defgroup ctimer Callback timer
* @{
*
* The ctimer module provides a timer mechanism that calls a specified
* C function when a ctimer expires.
*
*/
#ifndef CTIMER_H_
#define CTIMER_H_
#include "sys/etimer.h"
struct ctimer {
struct ctimer *next;
struct etimer etimer;
struct process *p;
void (*f)(void *);
void *ptr;
};
/**
* \brief Reset a callback timer with the same interval as was
* previously set.
* \param 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.
*
* \sa ctimer_restart()
*/
void ctimer_reset(struct ctimer *c);
/**
* \brief Restart a callback timer from the current point in time
* \param 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.
*
* \sa ctimer_reset()
*/
void ctimer_restart(struct ctimer *c);
/**
* \brief Set a callback timer.
* \param c A pointer to the callback timer.
* \param t The interval before the timer expires.
* \param f A function to be called when the timer expires.
* \param 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.
*
* This essentially does ctimer_set_process(c, t, f, ptr, PROCESS_CURRENT());
*
*/
void ctimer_set(struct ctimer *c, clock_time_t t,
void (*f)(void *), void *ptr);
/**
* \brief Set a callback timer.
* \param c A pointer to the callback timer.
* \param t The interval before the timer expires.
* \param f A function to be called when the timer expires.
* \param ptr An opaque pointer that will be supplied as an argument to the callback function.
* \param p A pointer to the process the timer belongs to
*
* 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.
*
*/
void ctimer_set_with_process(struct ctimer *c, clock_time_t t,
void (*f)(void *), void *ptr, struct process *p);
/**
* \brief Stop a pending callback timer.
* \param 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.
*
*/
void ctimer_stop(struct ctimer *c);
/**
* \brief Check if a callback timer has expired.
* \param c A pointer to the callback timer
* \return 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.
*/
int ctimer_expired(struct ctimer *c);
/**
* \brief Initialize the callback timer library.
*
* This function initializes the callback timer library and
* should be called from the system boot up code.
*/
void ctimer_init(void);
#endif /* CTIMER_H_ */
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/** @} */
/** @} */