如何在C中设置函数的超时？

#include<stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <unistd.h>
#include <stdbool.h>

#define TIMEOUT_SECONDS 5

void *functionToTimeout(void *arg) {
    // 在这里执行你的函数
    int result = 0;
    for (int i = 0; i < 1e9; i++) {
        result += i;
    }
    printf("Function completed with result: %d\n", result);

    // 释放互斥锁
    pthread_mutex_lock(&mutex);
    isFunctionCompleted = true;
    pthread_cond_signal(&cond);
    pthread_mutex_unlock(&mutex);
    return NULL;
}

int main() {
    pthread_t thread;
    pthread_mutex_init(&mutex, NULL);
    pthread_cond_init(&cond, NULL);
    isFunctionCompleted = false;

    // 创建新线程并执行函数
    pthread_create(&thread, NULL, functionToTimeout, NULL);

    // 等待函数完成或超时
    pthread_mutex_lock(&mutex);
    if (!isFunctionCompleted) {
        struct timespec ts;
        clock_gettime(CLOCK_REALTIME, &ts);
        ts.tv_sec += TIMEOUT_SECONDS;
        pthread_cond_timedwait(&cond, &mutex, &ts);
    }
    pthread_mutex_unlock(&mutex);

    // 检查函数是否已完成
    if (!isFunctionCompleted) {
        printf("Function timed out after %d seconds\n", TIMEOUT_SECONDS);
        // 取消线程
        pthread_cancel(thread);
    }

    // 清理
    pthread_join(thread, NULL);
    pthread_mutex_destroy(&mutex);
    pthread_cond_destroy(&cond);

    return 0;
}