linux信号量编程同步

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

#define NUM_THREADS 5

sem_t sem;

void* thread_func(void* arg) {
    sem_wait(&sem); // 等待信号量
    printf("Thread %ld is running\n", (long)arg);
    // 模拟工作
    sleep(1);
    printf("Thread %ld is done\n", (long)arg);
    sem_post(&sem); // 释放信号量
    pthread_exit(NULL);
}

int main() {
    pthread_t threads[NUM_THREADS];
    int rc;
    long t;

    sem_init(&sem, 0, 1); // 初始化信号量，初始值为1

    for (t = 0; t < NUM_THREADS; t++) {
        rc = pthread_create(&threads[t], NULL, thread_func, (void*)t);
        if (rc) {
            perror("pthread_create");
            exit(-1);
        }
    }

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

    sem_destroy(&sem); // 销毁信号量
    pthread_exit(NULL);
}