144 lines
3.9 KiB
C++
144 lines
3.9 KiB
C++
/*
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Adept MobileRobots Robotics Interface for Applications (ARIA)
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Copyright (C) 2004, 2005 ActivMedia Robotics LLC
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Copyright (C) 2006, 2007, 2008, 2009, 2010 MobileRobots Inc.
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Copyright (C) 2011, 2012, 2013 Adept Technology
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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If you wish to redistribute ARIA under different terms, contact
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Adept MobileRobots for information about a commercial version of ARIA at
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robots@mobilerobots.com or
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Adept MobileRobots, 10 Columbia Drive, Amherst, NH 03031; +1-603-881-7960
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*/
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#include <stdlib.h>
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#include <time.h>
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#include "Aria.h"
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/*
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This example is to show how to use a condition variable. Conditions
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are usefull for delaying the execution of a thread until some time later
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when some other part of the program wants to wake it up.
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This program has 5 threads. The main thread and 4 worker threads. The
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worker threads all wait on the condition variable to be woken up. When
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they are woken up they print that fact and then go right back to sleep
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waiting on the condition variable.
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The main thread randomly sleeps between 100ms and 500ms and then wakes
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up a single thread. It does this 10 times then tells all the threads
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to exit and waits for them to do so. The main thread then exits, which
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ends the program.
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This is simply an example of how to make threads wait for something to
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happen without doing a busy loop, which takes up CPU time.
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*/
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// The thread class
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class Task : public ArASyncTask
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{
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public:
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Task(int num, ArCondition *cond);
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virtual ~Task() {}
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// The run loop of the thread.
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void * runThread(void *arg);
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protected:
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int myNum;
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ArCondition *myCond;
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};
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// Constructor
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Task::Task(int num, ArCondition *cond) :
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myNum(num),
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myCond(cond)
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{
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setThreadName("Task");
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}
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// The main loop for the threads. It checks to see if its still running.
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// If not, it exits. The running variable is managed by ArThread. While its
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// running, it waits on the condition variable.
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void * Task::runThread(void *arg)
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{
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threadStarted();
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while (getRunning())
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{
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printf("Task %d waiting\n", myNum);
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myCond->wait();
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printf("Task %d woke up\n", myNum);
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}
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return(NULL);
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}
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int main()
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{
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int i, sleepTime;
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// The condition the threads will be using
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ArCondition cond;
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// The threads
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Task task1(1, &cond);
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Task task2(2, &cond);
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Task task3(3, &cond);
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Task task4(4, &cond);
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// Initialize Aria, which in turn initializes the thread layer
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Aria::init();
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// Initialize the rand() function
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srand((unsigned)time(NULL));
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// Lets start all correct threads.
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task1.create();
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task2.create();
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task3.create();
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task4.create();
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// Lets wake up the threads at different random times
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for (i=0; i<10; ++i)
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{
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sleepTime=rand()%400+100;
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printf("Main: Sleeping %dms\n", sleepTime);
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ArUtil::sleep(sleepTime);
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printf("Main: Waking up a thread\n");
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cond.signal();
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}
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printf("Exiting\n");
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// Stop all the threads, which sets their running variable to false
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ArThread::stopAll();
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// Now that all the threads are marked as not running, wake them up
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// so that we can exit the program gracefully.
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cond.broadcast();
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// Wait for all the threads to exit
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ArThread::joinAll();
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// Uninit Aria
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Aria::uninit();
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return(0);
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}
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