linux+sem+释放

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

sem_t sem;

void* thread_func(void* arg) {
    // 等待信号量
    sem_wait(&sem);
    printf("Thread %ld acquired the semaphore
", (long)arg);

    // 模拟对共享资源的访问
    sleep(1);

    // 释放信号量
    sem_post(&sem);
    printf("Thread %ld released the semaphore
", (long)arg);
    return NULL;
}

int main() {
    // 初始化信号量，初始值为1
    if (sem_init(&sem, 0, 1) == -1) {
        perror("sem_init");
        exit(EXIT_FAILURE);
    }

    pthread_t threads[5];
    for (long i = 0; i < 5; ++i) {
        if (pthread_create(&threads[i], NULL, thread_func, (void*)i) != 0) {
            perror("pthread_create");
            exit(EXIT_FAILURE);
        }
    }

    for (int i = 0; i < 5; ++i) {
        pthread_join(threads[i], NULL);
    }

    // 销毁信号量
    sem_destroy(&sem);
    return 0;
}