linux c线程池

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#include <stdio.h>  #include <stdlib.h>  #include <unistd.h>  #include <sys/types.h>  #include <pthread.h>  #include <assert.h>  /* *线程池里所有运行和等待的任务都是一个CThread_worker *由于所有任务都在链表里,所以是一个链表结构 */  typedef struct worker  {      /*回调函数,任务运行时会调用此函数,注意也可声明成其它形式*/      void *(*process) (void *arg);      void *arg;/*回调函数的参数*/      struct worker *next;      } CThread_worker;    /*线程池结构*/  typedef struct  {       pthread_mutex_t queue_lock;       pthread_cond_t queue_ready;          /*链表结构,线程池中所有等待任务*/       CThread_worker *queue_head;        /*是否销毁线程池*/      int shutdown;       pthread_t *threadid;      /*线程池中允许的活动线程数目*/      int max_thread_num;      /*当前等待队列的任务数目*/      int cur_queue_size;  } CThread_pool;    int pool_add_worker (void *(*process) (void *arg), void *arg);  void *thread_routine (void *arg);    static CThread_pool *pool = NULL;  void pool_init (int max_thread_num)//初始化线程池  {       pool = (CThread_pool *) malloc (sizeof (CThread_pool));         pthread_mutex_init (&(pool->queue_lock), NULL);       pthread_cond_init (&(pool->queue_ready), NULL);//?         pool->queue_head = NULL;         pool->max_thread_num = max_thread_num;       pool->cur_queue_size = 0;         pool->shutdown = 0;         pool->threadid =(pthread_t *) malloc (max_thread_num * sizeof (pthread_t));       int i = 0;       for (i = 0; i < max_thread_num; i++)       {           pthread_create (&(pool->threadid[i]), NULL, thread_routine,NULL);       }  }    /*向线程池中加入任务*/  int pool_add_worker (void *(*process) (void *arg), void *arg)  {      /*构造一个新任务*/       CThread_worker *newworker =(CThread_worker *) malloc (sizeof (CThread_worker));       newworker->process = process;       newworker->arg = arg;       newworker->next = NULL;/*别忘置空*/       pthread_mutex_lock (&(pool->queue_lock));      /*将任务加入到等待队列中*/       CThread_worker *member = pool->queue_head;      if (member != NULL)       {          while (member->next != NULL)               member = member->next;           member->next = newworker;       }      else       {           pool->queue_head = newworker;       }           assert (pool->queue_head != NULL);           pool->cur_queue_size++;       pthread_mutex_unlock (&(pool->queue_lock));      /*好了,等待队列中有任务了,唤醒一个等待线程;      注意如果所有线程都在忙碌,这句没有任何作用*/       pthread_cond_signal (&(pool->queue_ready));      return 0;  }    /*销毁线程池,等待队列中的任务不会再被执行,但是正在运行的线程会一直 把任务运行完后再退出*/  int pool_destroy ()  {      if (pool->shutdown)          return -1;/*防止两次调用*/       pool->shutdown = 1;          /*唤醒所有等待线程,线程池要销毁了*/       pthread_cond_broadcast (&(pool->queue_ready));          /*阻塞等待线程退出,否则就成僵尸了*/      int i;      for (i = 0; i < pool->max_thread_num; i++)           pthread_join (pool->threadid[i], NULL);       free (pool->threadid);          /*销毁等待队列*/       CThread_worker *head = NULL;       while (pool->queue_head != NULL)       {           head = pool->queue_head;           pool->queue_head = pool->queue_head->next;           free (head);       }      /*条件变量和互斥量也别忘了销毁*/       pthread_mutex_destroy(&(pool->queue_lock));       pthread_cond_destroy(&(pool->queue_ready));              free (pool);      /*销毁后指针置空是个好习惯*/       pool=NULL;      return 0;  }  void * thread_routine (void *arg)  {       printf ("starting thread 0x%x\n", pthread_self ());       while (1)       {           pthread_mutex_lock (&(pool->queue_lock));          /*如果等待队列为0并且不销毁线程池,则处于阻塞状态; 注意pthread_cond_wait是一个原子操作,等待前会解锁,唤醒后会加锁*/          while (pool->cur_queue_size == 0 && !pool->shutdown)           {               printf ("thread 0x%x is waiting\n", pthread_self ());               pthread_cond_wait (&(pool->queue_ready), &(pool->queue_lock));           }              /*线程池要销毁了*/          if (pool->shutdown)           {              /*遇到break,continue,return等跳转语句,千万不要忘记先解锁*/               pthread_mutex_unlock (&(pool->queue_lock));               printf ("thread 0x%x will exit\n", pthread_self ());               pthread_exit (NULL);           }               printf ("thread 0x%x is starting to work\n", pthread_self ());              /*assert是调试的好帮手*/           assert (pool->cur_queue_size != 0);           assert (pool->queue_head != NULL);                     /*等待队列长度减去1,并取出链表中的头元素*/           pool->cur_queue_size--;           CThread_worker *worker = pool->queue_head;           pool->queue_head = worker->next;           pthread_mutex_unlock (&(pool->queue_lock));              /*调用回调函数,执行任务*/           (*(worker->process)) (worker->arg);           free (worker);           worker = NULL;       }      /*这一句应该是不可达的*/       pthread_exit (NULL);  }     //   下面是测试代码    void *myprocess (void *arg)  {       printf ("threadid is 0x%x, working on task %d\n", pthread_self (),*(int *) arg);       sleep (1);/*休息一秒,延长任务的执行时间*/      return NULL;  }  int main (int argc, char **argv)  {      pool_init (3);/*线程池中最多三个活动线程*/             /*连续向池中投入10个任务*/      int *workingnum = (int *) malloc (sizeof (int) * 10);      int i;      for (i = 0; i < 10; i++)       {           workingnum[i] = i;           pool_add_worker (myprocess, &workingnum[i]);       }      /*等待所有任务完成*/       sleep (5);      /*销毁线程池*/          pool_destroy ();          free (workingnum);          return 0;  } 

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