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IDint pthread_detach(pthread_t tid);       //分离线程pthread_t pthread_self(void);            //自身ID

#include <stdio.h>#include <stdlib.h>#include <pthread.h>  //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 < max_thread_num; i++) {    pthread_create(&(pool->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 < pool->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;}