C语言线程池的常见实现方式详解

typedef struct {
    void (*routine)(void *arg);  // 任务执行的函数
    void *arg;                   // 传递给任务函数的参数
} task_t;

typedef struct {
    pthread_t *threads;           // 工作线程数组
    task_t *task_queue;           // 任务队列
    int queue_size;               // 队列大小
    int head, tail;               // 队列头尾索引
    int thread_count;             // 线程池中的线程数
    pthread_mutex_t lock;        // 锁，保护任务队列
    pthread_cond_t cond;         // 条件变量，唤醒工作线程
    int shutdown;                 // 是否关闭线程池
} thread_pool_t;

#include <pthread.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
typedef struct {
    void (*routine)(void *arg);  // 任务执行的函数
    void *arg;                   // 传递给任务函数的参数
} task_t;
typedef struct {
    pthread_t *threads;           // 工作线程数组
    task_t *task_queue;           // 任务队列
    int queue_size;               // 队列大小
    int head, tail;               // 队列头尾索引
    int thread_count;             // 线程池中的线程数
    pthread_mutex_t lock;        // 锁，保护任务队列
    pthread_cond_t cond;         // 条件变量，唤醒工作线程
    int shutdown;                 // 是否关闭线程池
} thread_pool_t;
void *worker(void *arg) {
    thread_pool_t *pool = (thread_pool_t *)arg;
    while (1) {
        pthread_mutex_lock(&pool->lock);
        while (pool->head == pool->tail && !pool->shutdown) {
            pthread_cond_wait(&pool->cond, &pool->lock);  // 等待任务
        }
        // 检查是否关闭线程池
        if (pool->shutdown) {
            pthread_mutex_unlock(&pool->lock);
            break;
        }
        task_t task = pool->task_queue[pool->head];  // 获取任务
        pool->head = (pool->head + 1) % pool->queue_size;  // 队列中移除任务
        pthread_mutex_unlock(&pool->lock);
        task.routine(task.arg);  // 执行任务
    }
    pthread_exit(NULL);
}
void thread_pool_init(thread_pool_t *pool, int thread_count, int queue_size) {
    pool->threads = (pthread_t *)malloc(thread_count * sizeof(pthread_t));
    pool->task_queue = (task_t *)malloc(queue_size * sizeof(task_t));
    pool->queue_size = queue_size;
    pool->head = pool->tail = 0;
    pool->thread_count = thread_count;
    pool->shutdown = 0;
    pthread_mutex_init(&pool->lock, NULL);
    pthread_cond_init(&pool->cond, NULL);
    // 创建线程
    for (int i = 0; i < thread_count; i++) {
        pthread_create(&pool->threads[i], NULL, worker, pool);
    }
}

void thread_pool_add_task(thread_pool_t *pool, void (*routine)(void *), void *arg) {
    pthread_mutex_lock(&pool->lock);
    // 检查任务队列是否满
    if ((pool->tail + 1) % pool->queue_size != pool->head) {
        pool->task_queue[pool->tail].routine = routine;
        pool->task_queue[pool->tail].arg = arg;
        pool->tail = (pool->tail + 1) % pool->queue_size;  // 更新队列尾部
        pthread_cond_signal(&pool->cond);  // 唤醒一个工作线程
    }
    pthread_mutex_unlock(&pool->lock);
}

void thread_pool_destroy(thread_pool_t *pool) {
    pthread_mutex_lock(&pool->lock);
    pool->shutdown = 1;
    pthread_cond_broadcast(&pool->cond);  // 唤醒所有线程，确保线程能够退出
    pthread_mutex_unlock(&pool->lock);
    // 等待所有线程退出
    for (int i = 0; i < pool->thread_count; i++) {
        pthread_join(pool->threads[i], NULL);
    }
    free(pool->threads);
    free(pool->task_queue);
    pthread_mutex_destroy(&pool->lock);
    pthread_cond_destroy(&pool->cond);
}

void print_hello(void *arg) {
    printf("Hello, %s!\n", (char *)arg);
}
int main() {
    thread_pool_t pool;
    thread_pool_init(&pool, 4, 10);  // 创建一个线程池，包含4个线程和10个任务队列
    for (int i = 0; i < 5; i++) {
        char *name = malloc(10);
        sprintf(name, "Task %d", i + 1);
        thread_pool_add_task(&pool, print_hello, name);
    }
    sleep(1);  // 等待任务执行
    thread_pool_destroy(&pool);  // 销毁线程池
    return 0;
}