Contiki-NG
lc.h
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1 /*
2  * Copyright (c) 2004-2005, 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
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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  * Author: Adam Dunkels <adam@sics.se>
32  *
33  */
34 
35 /**
36  * \addtogroup pt
37  * @{
38  */
39 
40 /**
41  * \defgroup lc Local continuations
42  * @{
43  *
44  * Local continuations form the basis for implementing protothreads. A
45  * local continuation can be <i>set</i> in a specific function to
46  * capture the state of the function. After a local continuation has
47  * been set can be <i>resumed</i> in order to restore the state of the
48  * function at the point where the local continuation was set.
49  *
50  *
51  */
52 
53 /**
54  * \file os/sys/lc.h
55  * Local continuations
56  * \author
57  * Adam Dunkels <adam@sics.se>
58  *
59  */
60 
61 #ifdef DOXYGEN
62 /**
63  * Initialize a local continuation.
64  *
65  * This operation initializes the local continuation, thereby
66  * unsetting any previously set continuation state.
67  *
68  * \hideinitializer
69  */
70 #define LC_INIT(lc)
71 
72 /**
73  * Set a local continuation.
74  *
75  * The set operation saves the state of the function at the point
76  * where the operation is executed. As far as the set operation is
77  * concerned, the state of the function does <b>not</b> include the
78  * call-stack or local (automatic) variables, but only the program
79  * counter and such CPU registers that needs to be saved.
80  *
81  * \hideinitializer
82  */
83 #define LC_SET(lc)
84 
85 /**
86  * Resume a local continuation.
87  *
88  * The resume operation resumes a previously set local continuation, thus
89  * restoring the state in which the function was when the local
90  * continuation was set. If the local continuation has not been
91  * previously set, the resume operation does nothing.
92  *
93  * \hideinitializer
94  */
95 #define LC_RESUME(lc)
96 
97 /**
98  * Mark the end of local continuation usage.
99  *
100  * The end operation signifies that local continuations should not be
101  * used any more in the function. This operation is not needed for
102  * most implementations of local continuation, but is required by a
103  * few implementations.
104  *
105  * \hideinitializer
106  */
107 #define LC_END(lc)
108 
109 /**
110  * \var typedef lc_t;
111  *
112  * The local continuation type.
113  *
114  * \hideinitializer
115  */
116 #endif /* DOXYGEN */
117 
118 #ifndef LC_H_
119 #define LC_H_
120 
121 #ifdef LC_CONF_INCLUDE
122 #include LC_CONF_INCLUDE
123 #else /* LC_CONF_INCLUDE */
124 #include "sys/lc-switch.h"
125 #endif /* LC_CONF_INCLUDE */
126 
127 #endif /* LC_H_ */
128 
129 /** @} */
130 /** @} */
Implementation of local continuations based on switch() statement.