linux 线程池

#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;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;CThread_worker *queue_end;    /*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){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->queue_end = 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)    {pool->queue_end->next = newworker;}else{pool->queue_head = newworker;    }pool->queue_end = 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;}}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;}