535 lines
14 KiB
C
535 lines
14 KiB
C
/*
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* Copyright (c) 2005, Swedish Institute of Computer Science
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the Institute nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* This file is part of the Contiki operating system.
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*
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* @(#)$Id: process.h,v 1.2 2006/08/17 15:39:25 bg- Exp $
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*/
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/**
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* \addtogroup sys
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* @{
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*/
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/**
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* \defgroup process Contiki processes
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*
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* A process in Contiki consists of a single \ref pt protothread.
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*
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* @{
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*/
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/**
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* \file
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* Header file for the Contiki process interface.
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* \author
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* Adam Dunkels <adam@sics.se>
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*
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*/
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#ifndef __PROCESS_H__
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#define __PROCESS_H__
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#include "sys/pt.h"
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#include "sys/cc.h"
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typedef unsigned char process_event_t;
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typedef void * process_data_t;
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typedef unsigned char process_num_events_t;
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/**
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* \name Return values
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* @{
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*/
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/**
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* \brief Return value indicating that an operation was successful.
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*
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* This value is returned to indicate that an operation
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* was successful.
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*/
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#define PROCESS_ERR_OK 0
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/**
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* \brief Return value indicating that the event queue was full.
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*
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* This value is returned from process_post() to indicate
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* that the event queue was full and that an event could
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* not be posted.
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*/
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#define PROCESS_ERR_FULL 1
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/* @} */
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#define PROCESS_NONE NULL
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#ifndef PROCESS_CONF_NUMEVENTS
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#define PROCESS_CONF_NUMEVENTS 32
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#endif /* PROCESS_CONF_NUMEVENTS */
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#define PROCESS_EVENT_NONE 0x80
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#define PROCESS_EVENT_INIT 0x81
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#define PROCESS_EVENT_POLL 0x82
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#define PROCESS_EVENT_EXIT 0x83
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#define PROCESS_EVENT_SERVICE_REMOVED 0x84
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#define PROCESS_EVENT_CONTINUE 0x85
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#define PROCESS_EVENT_MSG 0x86
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#define PROCESS_EVENT_EXITED 0x87
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#define PROCESS_EVENT_TIMER 0x88
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#define PROCESS_EVENT_MAX 0x89
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#define PROCESS_BROADCAST NULL
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#define PROCESS_ZOMBIE ((struct process *)0x1)
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/**
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* \name Process protothread functions
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* @{
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*/
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/**
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* Define the beginning of a process.
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*
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* This macro defines the beginning of a process, and must always
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* appear in a PROCESS_THREAD() definition. The PROCESS_END() macro
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* must come at the end of the process.
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*
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* \hideinitializer
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*/
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#define PROCESS_BEGIN() PT_BEGIN(process_pt)
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/**
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* Define the end of a process.
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*
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* This macro defines the end of a process. It must appear in a
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* PROCESS_THREAD() definition and must always be included. The
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* process exits when the PROCESS_END() macro is reached.
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*
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* \hideinitializer
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*/
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#define PROCESS_END() PT_END(process_pt)
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/**
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* Wait for an event to be posted to the process.
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*
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* This macro blocks the currently running process until the process
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* receives an event.
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*
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* \hideinitializer
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*/
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#define PROCESS_WAIT_EVENT() PROCESS_YIELD()
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/**
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* Wait for an event to be posted to the process, with an extra
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* condition.
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*
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* This macro is similar to PROCESS_WAIT_EVENT() in that it blocks the
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* currently running process until the process receives an event. But
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* PROCESS_WAIT_EVENT_UNTIL() takes an extra condition which must be
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* true for the process to continue.
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*
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* \param c The condition that must be true for the process to continue.
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* \sa PT_WAIT_UNTIL()
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*
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* \hideinitializer
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*/
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#define PROCESS_WAIT_EVENT_UNTIL(c) PROCESS_YIELD_UNTIL(c)
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/**
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* Yield the currently running process.
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*
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* \hideinitializer
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*/
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#define PROCESS_YIELD() PT_YIELD(process_pt)
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/**
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* Yield the currently running process until a condition occurs.
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*
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* This macro is different from PROCESS_WAIT_UNTIL() in that
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* PROCESS_YIELD_UNTIL() is guaranteed to always yield at least
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* once. This ensures that the process does not end up in an infinite
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* loop and monopolizing the CPU.
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*
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* \param c The condition to wait for.
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*
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* \hideinitializer
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*/
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#define PROCESS_YIELD_UNTIL(c) PT_YIELD_UNTIL(process_pt, c)
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/**
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* Wait for a condition to occur.
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*
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* This macro does not guarantee that the process yields, and should
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* therefore be used with care. In most cases, PROCESS_WAIT_EVENT(),
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* PROCESS_WAIT_EVENT_UNTIL(), PROCESS_YIELD() or
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* PROCESS_YIELD_UNTIL() should be used instead.
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*
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* \param c The condition to wait for.
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*
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* \hideinitializer
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*/
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#define PROCESS_WAIT_UNTIL(c) PT_WAIT_UNTIL(process_pt, c)
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/**
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* Exit the currently running process.
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*
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* \hideinitializer
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*/
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#define PROCESS_EXIT() PT_EXIT(process_pt)
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/**
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* Spawn a protothread from the process.
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*
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* \param pt The protothread state (struct pt) for the new protothread
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* \param thread The call to the protothread function.
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* \sa PT_SPAWN()
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*
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* \hideinitializer
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*/
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#define PROCESS_SPAWN(pt, thread) PT_SPAWN(process_pt, pt, thread)
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/**
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* Yield the process for a short while.
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*
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* This macro yields the currently running process for a short while,
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* thus letting other processes run before the process continues.
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*
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* \hideinitializer
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*/
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#define PROCESS_PAUSE() do { \
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process_post(PROCESS_CURRENT(), PROCESS_EVENT_CONTINUE, NULL); \
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PROCESS_WAIT_EVENT(); \
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} while(0)
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/** @} end of protothread functions */
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/**
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* \name Poll and exit handlers
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* @{
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*/
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/**
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* Specify an action when a process is polled.
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*
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* \note This declaration must come immediately before the
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* PROCESS_BEGIN() macro.
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*
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* \param handler The action to be performed.
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*
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* \hideinitializer
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*/
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#define PROCESS_POLLHANDLER(handler) if(ev == PROCESS_EVENT_POLL) { handler; }
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/**
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* Specify an action when a process exits.
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*
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* \note This declaration must come immediately before the
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* PROCESS_BEGIN() macro.
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*
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* \param handler The action to be performed.
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*
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* \hideinitializer
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*/
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#define PROCESS_EXITHANDLER(handler) if(ev == PROCESS_EVENT_EXIT) { handler; }
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/** @} */
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/**
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* \name Process declaration and definion
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* @{
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*/
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/**
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* Define the body of a process.
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*
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* This macro is used to define the body (protothread) of a
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* process. The process is called whenever an event occurs in the
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* system, A process always start with the PROCESS_BEGIN() macro and
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* end with the PROCESS_END() macro.
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*
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* \hideinitializer
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*/
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#define PROCESS_THREAD(name, ev, data) \
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static PT_THREAD(process_thread_##name(struct pt *process_pt, \
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process_event_t ev, \
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process_data_t data))
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#if PROCESS_LOADABLE
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#define PROCESS_LOAD(name) const struct process *process_load = &name;
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#else /* PROCESS_LOADABLE */
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#define PROCESS_LOAD(name)
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#endif /* PROCESS_LOADABLE */
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extern const struct process *process_load;
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/**
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* Declare the name of a process.
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*
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* This macro is typically used in header files to declare the name of
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* a process that is implemented in the C file.
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*
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* \hideinitializer
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*/
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#define PROCESS_NAME(name) extern struct process name
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/**
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* Declare a process that should not be automatically loaded.
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*
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* This macro is similar to the PROCESS() declaration, with the
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* difference that for programs that are compiled as loadable
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* programs, processes declared with the PROCESS_NOLOAD() declaration
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* will not be automatically started when the program is loaded.
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*
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* \hideinitializer
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*/
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#define PROCESS_NOLOAD(name, strname) \
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PROCESS_THREAD(name, ev, data); \
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struct process name = { NULL, strname, \
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process_thread_##name };
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/**
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* Declare a process.
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*
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* This macro declares a process. The process has two names: the
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* variable of the process structure, which is used by the C program,
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* and a human readable string name, which is used when debugging.
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*
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* \note For programs that are compiled as loadable programs: the
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* process declared with the PROCESS() declaration will be
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* automatically started when the program is loaded. The
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* PROCESS_NOLOAD() declaration can be used to declare a process that
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* shouldn't be automatically loaded.
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*
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* \param name The variable name of the process structure.
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* \param strname The string repressentation of the process' name.
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*
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* \hideinitializer
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*/
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#define PROCESS(name, strname) \
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PROCESS_NOLOAD(name, strname); \
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PROCESS_LOAD(name)
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/** @} */
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struct process {
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struct process *next;
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const char *name;
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PT_THREAD((* thread)(struct pt *, process_event_t, process_data_t));
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struct pt pt;
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unsigned char state;
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};
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/**
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* \name Functions called from application programs
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* @{
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*/
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/**
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* Start a process.
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*
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* \param p A pointer to a process structure.
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*
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* \param arg An argument pointer that can be passed to the new
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* process
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*
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*/
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void process_start(struct process *p, char *arg);
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/**
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* Post an asynchronous event.
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*
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* This function posts an asynchronous event to one or more
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* processes. The handing of the event is deferred until the target
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* process is scheduled by the kernel. An event can be broadcast to
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* all processes, in which case all processes in the system will be
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* scheduled to handle the event.
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*
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* \param ev The event to be posted.
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*
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* \param data The auxillary data to be sent with the event
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*
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* \param p The process to which the event should be posted, or
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* PROCESS_BROADCAST if the event should be posted to all processes.
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*
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* \retval PROCESS_ERR_OK The event could be posted.
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*
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* \retval PROCESS_ERR_FULL The event queue was full and the event could
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* not be posted.
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*/
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int process_post(struct process *p, process_event_t ev, process_data_t data);
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/**
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* Post a synchronous event to a process.
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*
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* \param p A pointer to the process' process structure.
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*
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* \param ev The event to be posted.
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*
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* \param data A pointer to additional data that is posted together
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* with the event.
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*/
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void process_post_synch(struct process *p,
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process_event_t ev, process_data_t data);
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/**
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* \brief Cause a process to exit
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* \param p The process that is to be exited
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*
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* This function causes a process to exit. The process can
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* either be the currently executing process, or another
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* process that is currently running.
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*
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* \sa PROCESS_CURRENT()
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*/
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void process_exit(struct process *p);
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/**
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* Get a pointer to the currently running process.
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*
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* This macro get a pointer to the currently running
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* process. Typically, this macro is used to post an event to the
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* current process with process_post().
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*
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* \hideinitializer
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*/
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#define PROCESS_CURRENT() process_current
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extern struct process *process_current;
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#define PROCESS_SET_FLAGS(flags)
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#define PROCESS_NO_BROADCAST
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/**
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* Switch context to another process
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*
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* This function switch context to the specified process and executes
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* the code as if run by that process. Typical use of this function is
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* to switch context in services, called by other processes. Each
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* PROCESS_CONTEXT_BEGIN() must be followed by the
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* PROCESS_CONTEXT_END() macro to end the context switch.
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*
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* Example:
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\code
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PROCESS_CONTEXT_BEGIN(&test_process);
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etimer_set(&timer, CLOCK_SECOND);
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PROCESS_CONTEXT_END(&test_process);
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\endcode
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*
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* \param p The process to use as context
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*
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* \sa PROCESS_CONTEXT_END()
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* \sa PROCESS_CURRENT()
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*/
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#define PROCESS_CONTEXT_BEGIN(p) {\
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struct process *tmp_current = PROCESS_CURRENT();\
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process_current = p
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/**
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* End a context switch
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*
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* This function ends a context switch and changes back to the
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* previous process.
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*
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* \param p The process used in the context switch
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*
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* \sa PROCESS_CONTEXT_START()
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*/
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#define PROCESS_CONTEXT_END(p) process_current = tmp_current; }
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/**
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* \brief Allocate a global event number.
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* \return The allocated event number
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*
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* In Contiki, event numbers above 128 are global and may
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* be posted from one process to another. This function
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* allocates one such event number.
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*
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* \note There currently is no way to deallocate an allocated event
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* number.
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*/
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process_event_t process_alloc_event(void);
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/** @} */
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/**
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* \name Functions called from device drivers
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* @{
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*/
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/**
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* Request a process to be polled.
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*
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* This function typically is called from an interrupt handler to
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* cause a process to be polled.
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*
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* \param p A pointer to the process' process structure.
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*/
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void process_poll(struct process *p);
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/** @} */
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/**
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* \name Functions called by the system and boot-up code
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* @{
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*/
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/**
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* \brief Initialize the process module.
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*
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* This function initializes the process module and should
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* be called by the system boot-up code.
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*/
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void process_init(void);
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/**
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* Run the system once - call poll handlers and process one event.
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*
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* This function should be called repeatedly from the main() program
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* to actually run the Contiki system. It calls the necessary poll
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* handlers, and processes one event. The function returns the number
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* of events that are waiting in the event queue so that the caller
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* may choose to put the CPU to sleep when there are no pending
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* events.
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*
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* \return The number of events that are currently waiting in the
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* event queue.
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*/
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int process_run(void);
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/**
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* Number of events waiting to be processed.
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*
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* \return The number of events that are currently waiting to be
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* processed.
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*/
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int process_nevents(void);
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/** @} */
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extern struct process *process_list;
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#define PROCESS_LIST() process_list
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#endif /* __PROCESS_H__ */
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/** @} */
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/** @} */
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