Contiki-NG
ctimer.h
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1 /*
2  * Copyright (c) 2006, Swedish Institute of Computer Science.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  * notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  * notice, this list of conditions and the following disclaimer in the
12  * documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the Institute nor the names of its contributors
14  * may be used to endorse or promote products derived from this software
15  * without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  * This file is part of the Contiki operating system.
30  *
31  */
32 
33 /**
34  * \file
35  * Header file for the callback timer
36  * \author
37  * Adam Dunkels <adam@sics.se>
38  */
39 
40 /**
41  * \addtogroup timers
42  * @{
43  */
44 
45 /**
46  * \defgroup ctimer Callback timer
47  * @{
48  *
49  * The ctimer module provides a timer mechanism that calls a specified
50  * C function when a ctimer expires.
51  *
52  * It is \e not safe to manipulate callback timers within an interrupt context.
53  */
54 
55 #ifndef CTIMER_H_
56 #define CTIMER_H_
57 
58 #include "contiki.h"
59 #include "sys/etimer.h"
60 
61 struct ctimer {
62  struct ctimer *next;
63  struct etimer etimer;
64  struct process *p;
65  void (*f)(void *);
66  void *ptr;
67 };
68 
69 /**
70  * \brief Reset a callback timer with the same interval as was
71  * previously set.
72  * \param c A pointer to the callback timer.
73  *
74  * This function resets the callback timer with the same
75  * interval that was given to the callback timer with the
76  * ctimer_set() function. The start point of the interval
77  * is the exact time that the callback timer last
78  * expired. Therefore, this function will cause the timer
79  * to be stable over time, unlike the ctimer_restart()
80  * function. If this is executed before the timer expired,
81  * this function has no effect.
82  *
83  * \sa ctimer_restart()
84  */
85 void ctimer_reset(struct ctimer *c);
86 
87 /**
88  * \brief Restart a callback timer from the current point in time
89  * \param c A pointer to the callback timer.
90  *
91  * This function restarts the callback timer with the same
92  * interval that was given to the ctimer_set()
93  * function. The callback timer will start at the current
94  * time.
95  *
96  * \note A periodic timer will drift if this function is
97  * used to reset it. For periodic timers, use the
98  * ctimer_reset() function instead.
99  *
100  * \sa ctimer_reset()
101  */
102 void ctimer_restart(struct ctimer *c);
103 
104 /**
105  * \brief Set a callback timer.
106  * \param c A pointer to the callback timer.
107  * \param t The interval before the timer expires.
108  * \param f A function to be called when the timer expires.
109  * \param ptr An opaque pointer that will be supplied as an argument to the callback function.
110  *
111  * This function is used to set a callback timer for a time
112  * sometime in the future. When the callback timer expires,
113  * the callback function f will be called with ptr as argument.
114  *
115  * This essentially does ctimer_set_process(c, t, f, ptr, PROCESS_CURRENT());
116  *
117  */
118 void ctimer_set(struct ctimer *c, clock_time_t t,
119  void (*f)(void *), void *ptr);
120 
121 /**
122  * \brief Set a callback timer.
123  * \param c A pointer to the callback timer.
124  * \param t The interval before the timer expires.
125  * \param f A function to be called when the timer expires.
126  * \param ptr An opaque pointer that will be supplied as an argument to the callback function.
127  * \param p A pointer to the process the timer belongs to
128  *
129  * This function is used to set a callback timer for a time
130  * sometime in the future. When the callback timer expires,
131  * the callback function f will be called with ptr as argument.
132  *
133  */
134 void ctimer_set_with_process(struct ctimer *c, clock_time_t t,
135  void (*f)(void *), void *ptr, struct process *p);
136 
137 /**
138  * \brief Stop a pending callback timer.
139  * \param c A pointer to the pending callback timer.
140  *
141  * This function stops a callback timer that has previously
142  * been set with ctimer_set(), ctimer_reset(), or ctimer_restart().
143  * After this function has been called, the callback timer will be
144  * expired and will not call the callback function.
145  *
146  */
147 void ctimer_stop(struct ctimer *c);
148 
149 /**
150  * \brief Check if a callback timer has expired.
151  * \param c A pointer to the callback timer
152  * \return Non-zero if the timer has expired, zero otherwise.
153  *
154  * This function tests if a callback timer has expired and
155  * returns true or false depending on its status.
156  */
157 int ctimer_expired(struct ctimer *c);
158 
159 /**
160  * \brief Initialize the callback timer library.
161  *
162  * This function initializes the callback timer library and
163  * should be called from the system boot up code.
164  */
165 void ctimer_init(void);
166 
167 #endif /* CTIMER_H_ */
168 /** @} */
169 /** @} */
int ctimer_expired(struct ctimer *c)
Check if a callback timer has expired.
Definition: ctimer.c:161
void ctimer_stop(struct ctimer *c)
Stop a pending callback timer.
Definition: ctimer.c:149
void ctimer_set_with_process(struct ctimer *c, clock_time_t t, void(*f)(void *), void *ptr, struct process *p)
Set a callback timer.
Definition: ctimer.c:106
void ctimer_init(void)
Initialize the callback timer library.
Definition: ctimer.c:91
void ctimer_reset(struct ctimer *c)
Reset a callback timer with the same interval as was previously set.
Definition: ctimer.c:125
Event timer header file.
void ctimer_set(struct ctimer *c, clock_time_t t, void(*f)(void *), void *ptr)
Set a callback timer.
Definition: ctimer.c:99
void ctimer_restart(struct ctimer *c)
Restart a callback timer from the current point in time.
Definition: ctimer.c:137
A timer.
Definition: etimer.h:76