linux c 线程池库

主要由两个文件组成一个threadpool.h头文件和一个threadpool.c源文件组成。
threadpool.c文件

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <assert.h>
#include "threadpool.h"

/**
 * 初始化线程池
*/
struct threadpool *threadpool_init(int thread_num, int queue_max_num)
{
    struct threadpool *pool = NULL;
    do
    {
        pool = malloc(sizeof(struct threadpool));
        if (NULL == pool)
        {
            printf("failed to malloc threadpool!\n");
            break;
        }
        pool->thread_num = thread_num;
        pool->queue_max_num = queue_max_num;
        pool->queue_cur_num = 0;
        pool->head = NULL;
        pool->tail = NULL;
        if (pthread_mutex_init(&(pool->mutex), NULL))
        {
            printf("failed to init mutex!\n");
            break;
        }
        if (pthread_cond_init(&(pool->queue_empty), NULL))
        {
            printf("failed to init queue_empty!\n");
            break;
        }
        if (pthread_cond_init(&(pool->queue_not_empty), NULL))
        {
            printf("failed to init queue_not_empty!\n");
            break;
        }
        if (pthread_cond_init(&(pool->queue_not_full), NULL))
        {
            printf("failed to init queue_not_full!\n");
            break;
        }
        pool->pthreads = malloc(sizeof(pthread_t) * thread_num);
        if (NULL == pool->pthreads)
        {
            printf("failed to malloc pthreads!\n");
            break;
        }
        pool->queue_close = 0;
        pool->pool_close = 0;
        int i;
        for (i = 0; i < pool->thread_num; ++i)
        {
            pthread_create(&(pool->pthreads[i]), NULL, threadpool_function, (void *)pool);
        }

        return pool;
    } while (0);

    return NULL;
}

/**
 * 向线程池中添加任务
*/
int threadpool_add_job(struct threadpool *pool, void *(*callback_function)(void *arg), void *arg)
{
    assert(pool != NULL);
    assert(callback_function != NULL);
    assert(arg != NULL);

    pthread_mutex_lock(&(pool->mutex));
    while ((pool->queue_cur_num == pool->queue_max_num) && !(pool->queue_close || pool->pool_close))
    {
        pthread_cond_wait(&(pool->queue_not_full), &(pool->mutex)); //队列满的时候就等待
    }
    if (pool->queue_close || pool->pool_close) //队列关闭或者线程池关闭就退出
    {
        pthread_mutex_unlock(&(pool->mutex));
        return -1;
    }
    struct job *pjob = (struct job *)malloc(sizeof(struct job));
    if (NULL == pjob)
    {
        pthread_mutex_unlock(&(pool->mutex));
        return -1;
    }
    pjob->callback_function = callback_function;
    pjob->arg = arg;
    pjob->next = NULL;
    if (pool->head == NULL)
    {
        pool->head = pool->tail = pjob;
        pthread_cond_broadcast(&(pool->queue_not_empty)); //队列空的时候，有任务来时就通知线程池中的线程：队列非空
    }
    else
    {
        pool->tail->next = pjob;
        pool->tail = pjob;
    }
    pool->queue_cur_num++;
    pthread_mutex_unlock(&(pool->mutex));
    return 0;
}

/**
 * 线程运行函数
*/
void *threadpool_function(void *arg)
{
    struct threadpool *pool = (struct threadpool *)arg;
    struct job *pjob = NULL;
    while (1) //死循环
    {
        pthread_mutex_lock(&(pool->mutex));
        while ((pool->queue_cur_num == 0) && !pool->pool_close) //队列为空时，就等待队列非空
        {
            pthread_cond_wait(&(pool->queue_not_empty), &(pool->mutex));
        }
        if (pool->pool_close) //线程池关闭，线程就退出
        {
            pthread_mutex_unlock(&(pool->mutex));
            // pthread_exit(NULL);
            break;
        }
        pool->queue_cur_num--;
        pjob = pool->head;
        if (pool->queue_cur_num == 0)
        {
            pool->head = pool->tail = NULL;
        }
        else
        {
            pool->head = pjob->next;
        }
        if (pool->queue_cur_num == 0)
        {
            pthread_cond_signal(&(pool->queue_empty)); //队列为空，就可以通知threadpool_destroy函数，销毁线程函数
        }
        if (pool->queue_cur_num == pool->queue_max_num - 1)
        {
            pthread_cond_broadcast(&(pool->queue_not_full)); //队列非满，就可以通知threadpool_add_job函数，添加新任务
        }
        pthread_mutex_unlock(&(pool->mutex));

        (*(pjob->callback_function))(pjob->arg); //线程真正要做的工作，回调函数的调用
        free(pjob);
        pjob = NULL;
    }
}

/**
 * 销毁线程池
*/
int threadpool_destroy(struct threadpool *pool)
{
    assert(pool != NULL);
    pthread_mutex_lock(&(pool->mutex));
    if (pool->queue_close || pool->pool_close) //线程池已经退出了，就直接返回
    {
        pthread_mutex_unlock(&(pool->mutex));
        return -1;
    }

    pool->queue_close = 1; //置队列关闭标志
    while (pool->queue_cur_num != 0)
    {
        pthread_cond_wait(&(pool->queue_empty), &(pool->mutex)); //等待队列为空
    }

    pool->pool_close = 1; //置线程池关闭标志
    pthread_mutex_unlock(&(pool->mutex));
    pthread_cond_broadcast(&(pool->queue_not_empty)); //唤醒线程池中正在阻塞的线程
    pthread_cond_broadcast(&(pool->queue_not_full));  //唤醒添加任务的threadpool_add_job函数
    int i;
    for (i = 0; i < pool->thread_num; ++i)
    {
        pthread_join(pool->pthreads[i], NULL); //等待线程池的所有线程执行完毕
    }

    pthread_mutex_destroy(&(pool->mutex)); //清理资源
    pthread_cond_destroy(&(pool->queue_empty));
    pthread_cond_destroy(&(pool->queue_not_empty));
    pthread_cond_destroy(&(pool->queue_not_full));
    free(pool->pthreads);
    struct job *p;
    while (pool->head != NULL)
    {
        p = pool->head;
        pool->head = p->next;
        free(p);
    }
    free(pool);
    return 0;
}

---

threadpool.h文件

#include <pthread.h>

/**
 * 任务结构体
*/
struct job
{
    void* (*callback_function)(void *arg);    //线程回调函数
    void *arg;                                //回调函数参数
    struct job *next;
};

/**
 * 线程池结构体
*/
struct threadpool
{
    int thread_num;                   //线程池中开启线程的个数
    int queue_max_num;                //队列中最大job的个数
    struct job *head;                 //指向job的头指针
    struct job *tail;                 //指向job的尾指针
    pthread_t *pthreads;              //线程池中所有线程的pthread_t
    pthread_mutex_t mutex;            //互斥信号量
    pthread_cond_t queue_empty;       //队列为空的条件变量
    pthread_cond_t queue_not_empty;   //队列不为空的条件变量
    pthread_cond_t queue_not_full;    //队列不为满的条件变量
    int queue_cur_num;                //队列当前的job个数
    int queue_close;                  //队列是否已经关闭
    int pool_close;                   //线程池是否已经关闭
};

/**
 * 函数名：                   threadpool_init
 * 函数描述：                 初始化线程池
 * 输入：                    [in] thread_num     线程池开启的线程个数
 *                          [in] queue_max_num  队列的最大job个数 
 * 输出：                    无
 * 返回：                    成功：线程池地址 失败：NULL
*/
struct threadpool* threadpool_init(int thread_num, int queue_max_num);

/**
 * 函数名：                    threadpool_add_job
 * 函数描述：                  向线程池中添加任务
 * 输入：                     [in] pool                  线程池地址
 *                           [in] callback_function     回调函数
 *                           [in] arg                     回调函数参数
 * 输出：                     无
 * 返回：                     成功：0 失败：-1
*/
int threadpool_add_job(struct threadpool *pool, void* (*callback_function)(void *arg), void *arg);

/**
 * 函数名：                    threadpool_destroy
 * 函数描述：                   销毁线程池
 * 输入：                      [in] pool  线程池地址
 * 输出：                      无
 * 返回：                      成功：0 失败：-1
*/
int threadpool_destroy(struct threadpool *pool);

/**
 * 函数名：                    threadpool_function
 * 函数描述：                  线程池中线程函数
 * 输入：                     [in] arg  线程池地址
 * 输出：                     无  
 * 返回：                     无
*/
void* threadpool_function(void* arg);