C语言实现一个简单的线程池(一)

（代码有参考网上的一些实现）还有几个功能需要慢慢的实现和一些bug需要改，比如实现线程池的动态增长：

详细请看我的github： https://github.com/chengshuguang/thread-pool

thread_pool.h

#ifndef THREAD_POOL_H
#define THREAD_POOL_H

#include 
#include 
#include 
#include 
#include 

typedef struct task
{
	void *(*taskfunc)(void *arg);//声明一个函数指针
	void *arg;//函数的参数
	struct task *next;
}task;

typedef struct thread_pool
{
	task *task_queue_head;//任务队列
	task *task_queue_end;//指向任务队列结尾
	int task_queue_size;

	pthread_t *thread_queue;//线程队列
	int thread_num;
	int idle_thread_num;//空闲线程数

	int is_pool_destroyed;

	pthread_mutex_t queue_mutex;//用来互斥访问任务队列
	pthread_cond_t queue_cond;
}thread_pool;


#ifdef __cplusplus
extern "C"{
#endif

extern thread_pool *pool;
extern int thread_pool_init(int thread_pool_size);
//extern void * thread_pool_entrance(void *arg);
extern int thread_pool_add_task(void *(*taskfunc)(void *arg), void *arg);
extern int thread_pool_destroy();

#ifdef __cplusplus
}
#endif

#endif //THREAD_POOL_H

thread_pool.c

#include "thread_pool.h"
#include 
thread_pool *pool = NULL;
void * thread_pool_entrance(void *arg)
{
	int thread_id = (int)arg;
	printf("thread %d is created\n",thread_id);

	while(1)
	{
		pthread_mutex_lock(&(pool->queue_mutex));
		while(pool->task_queue_size == 0 && !pool->is_pool_destroyed)//必须用while，防止假唤醒
		{
			pthread_cond_wait(&(pool->queue_cond),&(pool->queue_mutex));//等待的时候会解锁，唤醒后加锁
		}

		if(pool->is_pool_destroyed)
		{
			printf("thread %d exit!!!\n",thread_id);
			pthread_mutex_unlock(&(pool->queue_mutex));//中途退出最容易出错，注意要解锁
			pthread_exit(NULL);
		}

		pool->idle_thread_num--;//线程进入忙碌状态
		//从任务队列中取出任务
		task *work;
		work = pool->task_queue_head;
		pool->task_queue_head = pool->task_queue_head->next;
		if(pool->task_queue_head == NULL)
			pool->task_queue_end = NULL;

		pool->task_queue_size--;

		pthread_mutex_unlock(&(pool->queue_mutex));

		//回调函数
		(*(work->taskfunc))(work->arg);
		pool->idle_thread_num++;//线程空闲
	}
	return NULL;
}


int thread_pool_init(int thread_pool_size)
{
	pool = (thread_pool *)malloc(sizeof(thread_pool));//不要最先给线程池分配空间

	pool->is_pool_destroyed = 0;

	pool->task_queue_head = NULL;
	pool->task_queue_end = NULL;
	pool->task_queue_size = 0;

	pool->thread_num = thread_pool_size;
	pool->thread_queue = (pthread_t *)malloc(thread_pool_size * sizeof(pthread_t));
	pool->idle_thread_num = thread_pool_size;

	//创建线程
	int i, ret;
	for(i=0; ithread_queue[i]), NULL, thread_pool_entrance, (void *)i);
		if(ret < 0)
		{
			printf("thread create error!!!\n");
			thread_pool_destroy();//注意销毁，避免内存泄漏
			return -1;
		}
	}

	pthread_mutex_init(&(pool->queue_mutex), NULL);
	pthread_cond_init(&(pool->queue_cond), NULL);

	return 0;
}


typedef void *(*taskfunc)(void *arg);
int thread_pool_add_task(taskfunc func, void *arg)
{
	task *newtask;
	newtask = (task *)malloc(sizeof(task));
	newtask->taskfunc = func;
	newtask->arg = arg;
	newtask->next = NULL;

	pthread_mutex_lock(&(pool->queue_mutex));

	if(pool->task_queue_head == NULL)
	{
		pool->task_queue_head = pool->task_queue_end = newtask;
	}
	else
	{
		pool->task_queue_end = pool->task_queue_end->next = newtask;
	}
	pool->task_queue_size++;

	pthrea