C++线程池的简单实现方法

 int pthread_create(pthread_t *tidp, const pthread_attr_t *attr, (void*)(*start_rtn)(void *), void *arg); //创建 void pthread_exit(void *retval);　　　　　　　　　　　　//终止自身 int pthread_cancel(pthread_t tid); 　 　　　　　　　　 //终止其他.发送终止信号后目标线程不一定终止，要调用join函数等待 int pthread_join(pthread_t tid, void **retval);　　 //阻塞并等待其他线程 

 int pthread_attr_init(pthread_attr_t *attr);　　　　　　　　　　 //初始化属性 int pthread_attr_setdetachstate(pthread_attr_t *attr, int detachstate); //设置分离状态 int pthread_attr_destroy(pthread_attr_t *attr);　　　　　　　　　　 //销毁属性 

 int pthread_mutex_init(pthread_mutex_t *restrict mutex, const pthread_mutexattr_t *restrict attr); //初始化锁 int pthread_mutex_destroy(pthread_mutex_t *mutex); //销毁锁 int pthread_mutex_lock(pthread_mutex_t *mutex); //加锁 int pthread_mutex_trylock(pthread_mutex_t *mutex); //尝试加锁，上面lock的非阻塞版本 int pthread_mutex_unlock(pthread_mutex_t *mutex); //解锁 

 int pthread_cond_init(pthread_cond_t *cv, const pthread_condattr_t *cattr); //初始化 int pthread_cond_destroy(pthread_cond_t *cond);                 //销毁 int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex);     //等待条件 int pthread_cond_signal(pthread_cond_t *cond);                 //通知,唤醒第一个调用pthread_cond_wait()而进入睡眠的线程 

 int pthread_equal(pthread_t t1, pthread_t t2); //比较线程ID int pthread_detach(pthread_t tid);       //分离线程 pthread_t pthread_self(void);            //自身ID 

 #include  #include  #include   //linux环境中多线程的头文件，非C语言标准库，编译时最后要加 -lpthread 调用动态链接库 //工作链表的结构 typedef struct worker { void *(*process)(void *arg);  //工作函数 void *arg;           //函数的参数 struct worker *next; }CThread_worker; //线程池的结构 typedef struct { pthread_mutex_t queue_lock;   //互斥锁 pthread_cond_t queue_ready;  //条件变量/信号量 CThread_worker *queue_head;   //指向工作链表的头结点，临界区 int cur_queue_size;       //记录链表中工作的数量，临界区 int max_thread_num;       //最大线程数 pthread_t *threadid;      //线程ID int shutdown;          //开关 }CThread_pool; static CThread_pool *pool = NULL;  //一个线程池变量 int pool_add_worker(void *(*process)(void *arg), void *arg);  //负责向工作链表中添加工作 void *thread_routine(void *arg);  //线程例程 //线程池初始化 void pool_init(int max_thread_num) { int i = 0; pool = (CThread_pool *) malloc (sizeof(CThread_pool));  //创建线程池 pthread_mutex_init(&(pool->queue_lock), NULL);   //互斥锁初始化，参数为锁的地址 pthread_cond_init( &(pool->queue_ready), NULL);   //条件变量初始化，参数为变量地址 pool->queue_head = NULL; pool->cur_queue_size = 0; pool->max_thread_num = max_thread_num; pool->threadid = (pthread_t *) malloc(max_thread_num * sizeof(pthread_t)); for (i = 0; i threadid[i]), NULL, thread_routine, NULL); //创建线程, 参数为线程ID变量地址、属性、例程、参数 } pool->shutdown = 0; } //例程，调用具体的工作函数 void *thread_routine(void *arg) { printf("starting thread 0x%x\n", (int)pthread_self()); while(1) { pthread_mutex_lock(&(pool->queue_lock));  //从工作链表中取工作，要先加互斥锁，参数为锁地址 while(pool->cur_queue_size == 0 && !pool->shutdown) {    //链表为空 printf("thread 0x%x is waiting\n", (int)pthread_self()); pthread_cond_wait(&(pool->queue_ready), &(pool->queue_lock));  //等待资源，信号量用于通知。会释放第二个参数的锁，以供添加；函数返回时重新加锁。 } if(pool->shutdown) { pthread_mutex_unlock(&(pool->queue_lock));     //结束开关开启，释放锁并退出线程 printf("thread 0x%x will exit\n", (int)pthread_self()); pthread_exit(NULL);   //参数为void * } printf("thread 0x%x is starting to work\n", (int)pthread_self()); --pool->cur_queue_size; CThread_worker *worker = pool->queue_head; pool->queue_head = worker->next; pthread_mutex_unlock (&(pool->queue_lock));   //获取一个工作后释放锁 (*(worker->process))(worker->arg);   //做工作 free(worker); worker = NULL; } pthread_exit(NULL); } //销毁线程池 int pool_destroy() { if(pool->shutdown)   //检测结束开关是否开启，若开启，则所有线程会自动退出 return -1; pool->shutdown = 1; pthread_cond_broadcast( &(pool->queue_ready) );   //广播，唤醒所有线程，准备退出 int i; for(i = 0; i max_thread_num; ++i) pthread_join(pool->threadid[i], NULL);   //主线程等待所有线程退出，只有join第一个参数不是指针，第二个参数类型是void **，接收exit的返回值，需要强制转换 free(pool->threadid); CThread_worker *head = NULL; while(pool->queue_head != NULL) {      //释放未执行的工作链表剩余结点 head = pool->queue_head; pool->queue_head = pool->queue_head->next; free(head); } pthread_mutex_destroy(&(pool->queue_lock));   //销毁锁和条件变量 pthread_cond_destroy(&(pool->queue_ready)); free(pool); pool=NULL; return 0; } void *myprocess(void *arg) { printf("threadid is 0x%x, working on task %d\n", (int)pthread_self(), *(int*)arg); sleep (1); return NULL; } //添加工作 int pool_add_worker(void *(*process)(void *arg), void *arg) { CThread_worker *newworker = (CThread_worker *) malloc(sizeof(CThread_worker)); newworker->process = process;  //具体的工作函数 newworker->arg = arg; newworker->next = NULL; pthread_mutex_lock( &(pool->queue_lock) );   //加锁 CThread_worker *member = pool->queue_head;   //插入链表尾部 if( member != NULL ) { while( member->next != NULL ) member = member->next; member->next = newworker; } else { pool->queue_head = newworker; } ++pool->cur_queue_size; pthread_mutex_unlock( &(pool->queue_lock) );  //解锁 pthread_cond_signal( &(pool->queue_ready) );  //通知一个等待的线程 return 0; } int main(int argc, char **argv) { pool_init(3);  //主线程创建线程池，3个线程 int *workingnum = (int *) malloc(sizeof(int) * 10); int i; for(i = 0; i <10; ++i) { workingnum[i] = i; pool_add_worker(myprocess, &workingnum[i]);   //主线程负责添加工作，10个工作 } sleep (5); pool_destroy();   //销毁线程池 free (workingnum); return 0; }