linux 等待多个线程结束

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

#define NUM_THREADS 5

pthread_mutex_t mutex;
pthread_cond_t cond;
int ready = 0;

void* thread_func(void* arg) {
    int id = *(int*)arg;
    pthread_mutex_lock(&mutex);
    while (!ready) {
        pthread_cond_wait(&cond, &mutex);
    }
    printf("Thread %d is running.\n", id);
    pthread_mutex_unlock(&mutex);
    return NULL;
}

int main() {
    pthread_t threads[NUM_THREADS];
    int thread_ids[NUM_THREADS];

    pthread_mutex_init(&mutex, NULL);
    pthread_cond_init(&cond, NULL);

    for (int i = 0; i < NUM_THREADS; ++i) {
        thread_ids[i] = i;
        pthread_create(&threads[i], NULL, thread_func, &thread_ids[i]);
    }

    // 主线程准备就绪，唤醒所有等待的线程
    pthread_mutex_lock(&mutex);
    ready = 1;
    pthread_cond_broadcast(&cond);
    pthread_mutex_unlock(&mutex);

    for (int i = 0; i < NUM_THREADS; ++i) {
        pthread_join(threads[i], NULL);
    }

    pthread_mutex_destroy(&mutex);
    pthread_cond_destroy(&cond);

    return 0;
}