线程池代码（通用版）

#if !defined(__THREAD_POOL_H__)
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <memory.h>
#include <pthread.h>
#include <sys/types.h>

// 布尔类型
typedef int bool;
#define false (0)
#define true  (1)

/* 线程任务链表 */
typedef struct _thread_worker_t
{
	void *(*process)(void *arg);  /* 线程处理的任务 */
	void *arg;                    /* 任务接口参数 */
	struct _thread_worker_t *next;/* 下一个节点 */
}thread_worker_t;

/* 线程池对象 */
typedef struct
{
	pthread_mutex_t queue_lock;   /* 队列互斥锁 */
	pthread_cond_t queue_ready;   /* 队列条件锁 */

	thread_worker_t *head;        /* 任务队列头指针 */
	bool isdestroy;               /* 是否已销毁线程 */
	pthread_t *threadid;          /* 线程ID数组 —动态分配空间 */
	int num;                      /* 线程个数 */
	int queue_size;               /* 工作队列当前大小 */
}thread_pool_t;

/* 函数声明 */
extern int thread_pool_init(thread_pool_t **pool, int num);
extern int thread_pool_add_worker(thread_pool_t *pool, void *(*process)(void *arg), void *arg);
extern int thread_pool_destroy(thread_pool_t *pool);

#endif /*__THREAD_POOL_H__*/

/*************************************************************
 **功  能：线程池的初始化
 **参  数：
 **    pool：线程池对象
 **    num ：线程池中线程个数
 **返回值：0：成功 !0: 失败
 *************************************************************/
int thread_pool_init(thread_pool_t **pool, int num)
{
	int idx = 0;

        /* 为线程池分配空间 */
	*pool = (thread_pool_t*)calloc(1, sizeof(thread_pool_t));
	if(NULL == *pool)
	{
		return -1;
	}

        /* 初始化线程池 */
	pthread_mutex_init(&((*pool)->queue_lock), NULL);
	pthread_cond_init(&((*pool)->queue_ready), NULL);
	(*pool)->head = NULL;
	(*pool)->num = num;
	(*pool)->queue_size = 0;
	(*pool)->isdestroy = false;
	(*pool)->threadid = (pthread_t*)calloc(1, num*sizeof(pthread_t));
	if(NULL == (*pool)->threadid)
	{
		free(*pool);
		(*pool) = NULL;

		return -1;
	}

        /* 依次创建线程 */
	for(idx=0; idx<num; idx++)
	{
		pthread_create(&((*pool)->threadid[idx]), NULL, thread_routine, *pool);
	}

	return 0;
}

/*************************************************************
 **功  能：将任务加入线程池处理队列
 **参  数：
 **    pool：线程池对象
 **    process：需处理的任务
 **    arg: process函数的参数
 **返回值：0：成功 !0: 失败
 *************************************************************/
int thread_pool_add_worker(thread_pool_t *pool, void *(*process)(void *arg), void *arg)
{
	thread_worker_t *worker=NULL, *member=NULL;
	
	worker = (thread_worker_t*)calloc(1, sizeof(thread_worker_t));
	if(NULL == worker)
	{
		return -1;
	}

	worker->process = process;
	worker->arg = arg;
	worker->next = NULL;

	pthread_mutex_lock(&(pool->queue_lock));

	member = pool->head;
	if(NULL != member)
	{
		while(NULL != member->next) member = member->next;
		member->next = worker;
	}
	else
	{
		pool->head = worker;
	}

	pool->queue_size++;

	pthread_mutex_unlock(&(pool->queue_lock));
	pthread_cond_signal(&(pool->queue_ready));

	return 0;
}

/*************************************************************
 **功  能：线程池的销毁
 **参  数：
 **    pool：线程池对象
 **返回值：0：成功 !0: 失败
 *************************************************************/
int thread_pool_destroy(thread_pool_t *pool)
{
	int idx = 0;
	thread_worker_t *member = NULL;

	if(false != pool->isdestroy)
	{
		return -1;
	}

	pool->isdestroy = true;

	pthread_cond_broadcast(&(pool->queue_ready));
	for(idx=0; idx<pool->num; idx++)
	{
		pthread_join(pool->threadid[idx], NULL);
	}

	free(pool->threadid);
	pool->threadid = NULL;

	while(NULL != pool->head)
	{
		member = pool->head;
		pool->head = member->next;
		free(member);
	}

	pthread_mutex_destroy(&(pool->queue_lock));
	pthread_cond_destroy(&(pool->queue_ready));
	free(pool);
	
	return 0;
}

/*************************************************************
 **功  能：线程池各个线程入口函数
 **参  数：
 **    arg：线程池对象
 **返回值：0：成功 !0: 失败
 *************************************************************/
static void *thread_routine(void *arg)
{
	thread_worker_t *worker = NULL;
	thread_pool_t *pool = (thread_pool_t*)arg;

	while(1)
	{
		pthread_mutex_lock(&(pool->queue_lock));
		while((false == pool->isdestroy) && (0 == pool->queue_size))
		{
			pthread_cond_wait(&(pool->queue_ready), &(pool->queue_lock));
		}

		if(false != pool->isdestroy)
		{
			pthread_mutex_unlock(&(pool->queue_lock));
			pthread_exit(NULL);
		}

		pool->queue_size--;
		worker = pool->head;
		pool->head = worker->next;
		pthread_mutex_unlock(&(pool->queue_lock));

                /* 执行队列中的任务 */
		(*(worker->process))(worker->arg);

		free(worker);
		worker = NULL;
	}
}