#C 语言标准库头文件 threads.h

这个头文件提供 线程 相关的功能。例如线程控制、互斥量、条件变量、线程局部存储等。

#常量

#类型

#函数

#推荐阅读

• Standard library header <threads.h>

#示例

#include <stdio.h>
#include <threads.h>
#include <stdlib.h>

// 示例1: 简单的线程函数
int simple_thread(void *arg) {
    int *id = (int*)arg;
    printf("线程 %d 正在运行\n", *id);
    return 0;
}

// 示例2: 带互斥锁的线程函数
mtx_t mutex;
int shared_counter = 0;

int counter_thread(void *arg) {
    int *iterations = (int*)arg;
    
    for (int i = 0; i < *iterations; ++i) {
        mtx_lock(&mutex);
        shared_counter++;
        mtx_unlock(&mutex);
    }
    
    return 0;
}

// 示例3: 使用条件变量
cnd_t condition;
mtx_t condition_mutex;
int data_ready = 0;

int producer_thread(void *arg) {
    int *value = (int*)arg;
    
    mtx_lock(&condition_mutex);
    printf("生产者: 生成数据 %d\n", *value);
    data_ready = 1;
    cnd_signal(&condition);
    mtx_unlock(&condition_mutex);
    
    return 0;
}

int consumer_thread(void *arg) {
    (void)arg; // 未使用参数
    
    mtx_lock(&condition_mutex);
    while (!data_ready) {
        printf("消费者: 等待数据...\n");
        cnd_wait(&condition, &condition_mutex);
    }
    printf("消费者: 接收到数据\n");
    mtx_unlock(&condition_mutex);
    
    return 0;
}

// 示例函数: 演示线程创建和使用
int main(void) {
    thrd_t threads[3];
    int ids[3] = {1, 2, 3};
    
    printf("=== 简单线程示例 ===\n");
    for (int i = 0; i < 3; i++) {
        thrd_create(&threads[i], simple_thread, &ids[i]);
    }
    
    for (int i = 0; i < 3; i++) {
        thrd_join(threads[i], NULL);
    }
    
    printf("\n=== 互斥锁示例 ===\n");
    mtx_init(&mutex, mtx_plain);
    int iterations = 100000;
    thrd_t t1, t2;
    
    thrd_create(&t1, counter_thread, &iterations);
    thrd_create(&t2, counter_thread, &iterations);
    
    thrd_join(t1, NULL);
    thrd_join(t2, NULL);
    
    printf("最终计数器值: %d (应为: %d)\n", shared_counter, 2 * iterations);
    mtx_destroy(&mutex);
    
    printf("\n=== 条件变量示例 ===\n");
    mtx_init(&condition_mutex, mtx_plain);
    cnd_init(&condition);
    
    int value = 42;
    thrd_t producer, consumer;
    
    thrd_create(&consumer, consumer_thread, NULL);
    thrd_sleep(&(struct timespec){.tv_sec=1}, NULL); // 让消费者先启动
    thrd_create(&producer, producer_thread, &value);
    
    thrd_join(producer, NULL);
    thrd_join(consumer, NULL);
    
    mtx_destroy(&condition_mutex);
    cnd_destroy(&condition);

    return 0;
}

运行结果：

=== 简单线程示例 ===
线程 1 正在运行
线程 2 正在运行
线程 3 正在运行

=== 互斥锁示例 ===
最终计数器值: 200000 (应为: 200000)

=== 条件变量示例 ===
消费者: 等待数据...
生产者: 生成数据 42
消费者: 接收到数据