//当已经有人物放到队列里面后，就会受到通知，然后从底部拿走工作，在workerArg中返回
bool ThreadPool::fetchWork(WorkerThread **workerArg)
{
?sem_wait(&availableWork);

?pthread_mutex_lock(&mutexSync);
?WorkerThread * workerThread = workerQueue[bottomIndex];
? ? workerQueue[bottomIndex] = NULL;
?*workerArg = workerThread;
?if(queueSize !=1 )
? bottomIndex = (bottomIndex+1) % (queueSize-1);
?sem_post(&availableThreads);
?pthread_mutex_unlock(&mutexSync);
? ? return true;
}

//每个线程运行的静态函数实体，executeThis 方法将会被继承累从写，之后实现具体线程的工作。
void *ThreadPool::threadExecute(void *param)
{
?WorkerThread *worker = NULL;
?while(((ThreadPool *)param)->fetchWork(&worker))
?{
? if(worker)
? ? ? ? {
? ?worker->executeThis();
? ? ? ? ? ? //cout << "worker[" << worker->id << "]\tdelete address: [" << worker << "]" << endl;
? ? ? ? ? ? delete worker;
? ? ? ? ? ? worker = NULL;
? ? ? ? }

? pthread_mutex_lock( &(((ThreadPool *)param)->mutexWorkCompletion) );
? ? ? ? //cout << "Thread " << pthread_self() << " has completed a Job !" << endl;
? ?((ThreadPool *)param)->incompleteWork--;
? pthread_mutex_unlock( &(((ThreadPool *)param)->mutexWorkCompletion) );
?}
?return 0;
}

?

?

#include
#include "threadpool.h"

using namespace std;

#define ITERATIONS 20

class SampleWorkerThread : public WorkerThread
{
public:
? ? int id;
?unsigned virtual executeThis()
?{
?// Instead of sleep() we could do anytime consuming work here.
?// Using ThreadPools is advantageous only when the work to be done is really time consuming. (atleast 1 or 2 seconds)
? cout<<"This is SampleWorkerThread sleep 2s"<? sleep(2);
? return(0);
?}

? ? SampleWorkerThread(int id) : WorkerThread(id), id(id)
? ? {
//? ? ? cout << "Creating SampleWorkerThread " << id << "\t address=" << this << endl;
? ? }

? ? ~SampleWorkerThread()
? ? {
//? ? ? cout << "Deleting SampleWorkerThread " << id << "\t address=" << this << endl;
? ? }
};

int main(int argc, char **argv)
{
?
?cout<<"Thread pool"<?ThreadPool* myPool = new ThreadPool(25);
?//pthread_create()执行，开始等待任务分配
?myPool->initializeThreads();

?//用来计算时间间隔。
? ? time_t t1=time(NULL);

?//分配具体工作到线程池
?for(unsigned int i=0;i? SampleWorkerThread* myThreathreadExecuted = new SampleWorkerThread(i);
? myPool->assignWork(myThreathreadExecuted);
?}
?
?//销毁钱等待所有线程结束，等待间隔为2秒。
? ? myPool->destroyPool(2);

? ? time_t t2=time(NULL);
? ? cout << t2-t1 << " seconds elapsed\n" << endl;
?delete myPool;
?
? ? return 0;
}

将C语言梳理一下，分布在以下10个章节中：