进程通信 | 进程共享一块内存

c/c++实现

#include 
#include 
#include 
#include 
#include 
#include 

int main() {
    key_t key;
    int shmid;
    int *shared_memory;
    int *value;

    // 生成一个唯一的键
    key = ftok("shared_memory_example", 'R');
    if (key == -1) {
        perror("ftok");
        exit(1);
    }

    // 创建或获取共享内存区域
    shmid = shmget(key, sizeof(int), 0666 | IPC_CREAT);
    if (shmid == -1) {
        perror("shmget");
        exit(1);
    }

    // 将共享内存附加到当前进程
    shared_memory = (int *)shmat(shmid, NULL, 0);
    if (shared_memory == (int *)-1) {
        perror("shmat");
        exit(1);
    }

    // 在共享内存中写入一个整数值
    *shared_memory = 42;

    // 创建一个新进程
    pid_t pid = fork();

    if (pid == 0) {
        // 子进程从共享内存中读取整数值
        printf("Child Process: Read from shared memory: %d\n", *shared_memory);
    } else if (pid > 0) {
        // 父进程等待子进程完成
        wait(NULL);
        printf("Parent Process: Read from shared memory: %d\n", *shared_memory);
    } else {
        perror("fork");
        exit(1);
    }

    // 分离共享内存
    shmdt(shared_memory);

    // 删除共享内存区域
    shmctl(shmid, IPC_RMID, NULL);

    return 0;
}