下面是原文链接，我是照着敲的。。。hi.baidu.com/boahegcrmdghots/item/f3ca1a3c2d47fcc52e8ec2e1

#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thread_job
由于所有任务都在链表中，所以是一个链表结构
*/
typedef struct job
{/*回调函数，任务运行时会调用次函数，注意也可以声明为其他形式*/void * (*process)(void *arg);void *arg;struct job *next;
}thread_job;/*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*/thread_job *queue_head;/*线程池销毁标记*/int destroy;/**/pthread_t *threadid;/*线程池中允许的最大线程数目*/int max_thread_num;/*等待队列的任务数目*/int cur_queue_size;
}thread_pool;int add_job(void *(*process)(void *arg), void *arg);
void *thread_runtine(void *arg);/*把线程池指针设为静态*/
static thread_pool *pool = NULL;/*初始化线程池*/
void pool_init(int max_thread_num)
{pool = (thread_pool *)malloc(sizeof(thread_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;/*为线程池中的各个线程分配空间 做初始化*/pool->threadid = (pthread_t *)malloc(max_thread_num*sizeof(pthread_t));int i = 0;/*创建max_thread_num个线程*/for(i=0; i<max_thread_num; i++){/*理解线程创建函数各个参数, 每个线程都会执行thread_runtine函数*/pthread_create(&(pool->threadid[i]), NULL, thread_runtine, NULL);}
}
/*每个线程都会执行runtine函数, 每个thread_rutine函数都是取出一个thread_job处理任务
也就是说，线程池中可能有很多个thread_job需要cur_queue_size个线程去处理,处理前要
先对线程池加锁，保证当前处理任务的线程处理thread_job时不会收到其他线程影响,能够互斥访问*/
void *thread_runtine(void *arg)
{printf("starting thread 0x%x\n", (unsigned int)pthread_self());while(1){/*对线程池加互斥锁*/pthread_mutex_lock(&(pool->queue_lock));/*如果线程当前的等待队列为0,并且没有被销毁，则处于阻塞状态pthread_cond_wait是一个原子操作，等待前解锁，唤醒后会加锁*/while( (pool->cur_queue_size == 0) && (!pool->destroy) ){printf("thread 0x%x is waiting\n", (unsigned int)pthread_self());pthread_cond_wait(&(pool->queue_ready), &(pool->queue_lock));}/*线程池销毁了*/if(pool->destroy){pthread_mutex_lock(&(pool->queue_lock));printf("thread 0x%x will exit\n", (unsigned int)pthread_self());pthread_exit(NULL);}printf("thread 0x%x is starting to work\n", (unsigned int)pthread_self());assert(pool->cur_queue_size != 0);assert(pool->queue_head != NULL);/*等待队列长度减1,并取出线程池中的线程链表中的头元素*/pool->cur_queue_size--;thread_job *job = pool->queue_head;pool->queue_head = job->next;pthread_mutex_unlock(&(pool->queue_lock));/*调用回调函数，执行任务, */(*(job->process))(job->arg);free(job);job = NULL;}/*这一句是不可达的*/pthread_exit(NULL);
}
/*向线程池中添加任务, 重点理解参数, 每个任务要做的事体现在process回调函数上*/
int pool_add_job(void *(*process)(void *arg), void *arg)
{thread_job *newjob = (thread_job *)malloc(sizeof(thread_job));newjob->process = process;newjob->arg = arg;newjob->next = NULL;/*对线程池加锁*/pthread_mutex_lock(&(pool->queue_lock));thread_job *member = pool->queue_head;if(member != NULL){while(member->next != NULL)member = member->next;member->next = newjob;}else{pool->queue_head = newjob;}assert(pool->queue_head != NULL);pool->cur_queue_size++;pthread_mutex_unlock(&(pool->queue_lock));/*等待队列中有任务了，唤醒一个等待线程，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;
}int pool_destroy()
{if(pool->destroy)return -1;pool->destroy = 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，否则变成僵尸了*/int i = 0;for(i=0; i<pool->max_thread_num; i++){pthread_join(pool->threadid[i], NULL);}free(pool->threadid);thread_job *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要销毁*/pthread_mutex_destroy(&(pool->queue_lock));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", (unsigned int)pthread_self(), *(int *)arg);sleep(1);return NULL;
}   int main(int argc, char **argv)
{pool_init(3);/*初始话含有3个线程的线程池*/int *workingnum = (int *)malloc(sizeof(int)*10);int i = 0;for(i=0; i<10; i++){workingnum[i] = i;pool_add_job(myprocess, &workingnum[i]);}sleep(5);pool_destroy();free(workingnum);return 0;
}