C++在Linux上如何进行进程间通信

#include <iostream>
#include <unistd.h>

int main() {
    int pipefd[2];
    pid_t pid;
    char buffer[10];

    // 创建管道
    if (pipe(pipefd) == -1) {
        perror("pipe");
        exit(EXIT_FAILURE);
    }

    // 创建子进程
    pid = fork();
    if (pid == -1) {
        perror("fork");
        exit(EXIT_FAILURE);
    }

    if (pid == 0) { // 子进程
        close(pipefd[1]); // 关闭写端
        read(pipefd[0], buffer, sizeof(buffer));
        std::cout << "Child received: " << buffer << std::endl;
        close(pipefd[0]);
    } else { // 父进程
        close(pipefd[0]); // 关闭读端
        write(pipefd[1], "Hello from parent", 18);
        close(pipefd[1]);
    }

    return 0;
}

#include <iostream>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

int main() {
    const char* fifo_name = "/tmp/myfifo";
    mkfifo(fifo_name, 0666);

    int fd = open(fifo_name, O_RDWR);
    if (fd == -1) {
        perror("open");
        exit(EXIT_FAILURE);
    }

    const char* message = "Hello from FIFO";
    write(fd, message, strlen(message) + 1);

    char buffer[10];
    read(fd, buffer, sizeof(buffer));
    std::cout << "Received: " << buffer << std::endl;

    close(fd);
    unlink(fifo_name);

    return 0;
}

#include <iostream>
#include <sys/ipc.h>
#include <sys/msg.h>
#include <cstring>

struct msg_buffer {
    long msg_type;
    char msg_text[100];
};

int main() {
    key_t key = ftok("msgqueue.c", 65);
    int msgid = msgget(key, 0666 | IPC_CREAT);

    if (msgid == -1) {
        perror("msgget");
        exit(EXIT_FAILURE);
    }

    msg_buffer buffer;
    buffer.msg_type = 1;
    strcpy(buffer.msg_text, "Hello from message queue");

    if (msgsnd(msgid, &buffer, sizeof(buffer.msg_text), 0) == -1) {
        perror("msgsnd");
        exit(EXIT_FAILURE);
    }

    if (msgrcv(msgid, &buffer, sizeof(buffer.msg_text), 1, 0) == -1) {
        perror("msgrcv");
        exit(EXIT_FAILURE);
    }

    std::cout << "Received: " << buffer.msg_text << std::endl;

    msgctl(msgid, IPC_RMID, NULL);

    return 0;
}

#include <iostream>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <cstring>

int main() {
    key_t key = ftok("shmfile.c", 65);
    int shmid = shmget(key, 1024, 0666 | IPC_CREAT);

    if (shmid == -1) {
        perror("shmget");
        exit(EXIT_FAILURE);
    }

    char* str = (char*) shmat(shmid, (void*)0, 0);
    if (str == (char*)(-1)) {
        perror("shmat");
        exit(EXIT_FAILURE);
    }

    strcpy(str, "Hello from shared memory");

    std::cout << "Message written in memory: " << str << std::endl;

    shmdt(str);

    return 0;
}

#include <iostream>
#include <sys/ipc.h>
#include <sys/sem.h>
#include <sys/types.h>
#include <unistd.h>

union semun {
    int val;
    struct semid_ds *buf;
    unsigned short *array;
};

int main() {
    key_t key = ftok("semaphore.c", 65);
    int semid = semget(key, 1, 0666 | IPC_CREAT);

    if (semid == -1) {
        perror("semget");
        exit(EXIT_FAILURE);
    }

    union semun arg;
    arg.val = 1; // 初始化信号量为1
    if (semctl(semid, 0, SETVAL, arg) == -1) {
        perror("semctl");
        exit(EXIT_FAILURE);
    }

    // P操作（等待信号量）
    struct sembuf sb = {0, -1, SEM_UNDO};
    if (semop(semid, &sb, 1) == -1) {
        perror("semop");
        exit(EXIT_FAILURE);
    }

    std::cout << "Semaphore value: " << arg.val << std::endl;

    // V操作（释放信号量）
    sb.sem_op = 1;
    if (semop(semid, &sb, 1) == -1) {
        perror("semop");
        exit(EXIT_FAILURE);
    }

    semctl(semid, 0, IPC_RMID, arg);

    return 0;
}

#include <iostream>
#include <sys/socket.h>
#include <sys/un.h>
#include <unistd.h>
#include <string.h>

int main() {
    struct sockaddr_un addr;
    int sockfd, newsockfd;
    socklen_t addr_len = sizeof(addr);
    char buffer[1024];

    // 创建套接字
    sockfd = socket(AF_UNIX, SOCK_STREAM, 0);
    if (sockfd == -1) {
        perror("socket");
        exit(EXIT_FAILURE);
    }

    // 设置地址
    memset(&addr, 0, sizeof(addr));
    addr.sun_family = AF_UNIX;
    strncpy(addr.sun_path, "/tmp/unix_socket", sizeof(addr.sun_path) - 1);

    // 绑定套接字
    if (bind(sockfd, (struct sockaddr*)&addr, addr_len) == -1) {
        perror("bind");
        exit(EXIT_FAILURE);
    }

    // 监听连接
    listen(sockfd, 5);
    newsockfd = accept(sockfd, (struct sockaddr*)&addr, &addr_len);
    if (newsockfd == -1) {
        perror("accept");
        exit(EXIT_FAILURE);
    }

    // 接收数据
    read(newsockfd, buffer, sizeof(buffer));
    std::cout << "Received: " << buffer << std::endl;

    // 发送数据
    const char* message = "Hello from UNIX socket";
    write(newsockfd, message, strlen(message) + 1);

    close(newsockfd);
    close(sockfd);

    return 0;
}