网络编程 笔记（七） 进程间通信

通过管道（PIPE）实现进程间通信

#include <stdio.h>
#include <unistd.h>
#define BUF_SIZE 30

int main(int argc, char *argv[])
{
    int fds[2];
    char str[] = "Who are you?";
    char buf[BUF_SIZE];
    pid_t pid;

    pipe(fds);
    pid = fork();
    if (pid == 0) {
        write(fds[1], str, sizeof(str));
    }
    else{
        read(fds[0], buf, BUF_SIZE);
        puts(buf);
    }

    return  0;
}

通过管道（PIPE）实现进程间双向通信

#include <stdio.h>
#include <unistd.h>
#define BUF_SIZE 30

int main(int argc, char *argv[])
{
    int fds[2];
    char str1[] = "Who are you?";
    char str2[] = "Thank you for your message";
    char buf[BUF_SIZE];
    pid_t pid;

    pipe(fds);
    pid = fork();
    if (pid == 0) {
        write(fds[1], str1, sizeof(str1));
        sleep(2);
        read(fds[0], buf, BUF_SIZE);
        printf("Child proc output : %s\n", buf);
    }
    else{
        read(fds[0], buf, BUF_SIZE);
        printf("Parent proc output : %s\n", buf);
        write(fds[1], str2, sizeof(str2));
        sleep(3);
    }

    return  0;
}

• 向管道传递数据时，先读到进程会把数据取走

双管道双向进程间通信

#include <stdio.h>
#include <unistd.h>
#define BUF_SIZE 30

int main(int argc, char *argv[])
{
    int fds1[2], fds2[2];
    char str1[] = "Who are you?";
    char str2[] = "Thank you for your message";
    char buf[BUF_SIZE];
    pid_t pid;

    pipe(fds1), pipe(fds2);
    pid = fork();
    if (pid == 0) {
        write(fds1[1], str1, sizeof(str1));
        read(fds2[0], buf, BUF_SIZE);
        printf("Child proc output : %s\n", buf);
    }
    else{
        read(fds1[0], buf, BUF_SIZE);
        printf("Parent proc output : %s\n", buf);
        write(fds2[1], str2, sizeof(str2));
        sleep(3);
    }

    return  0;
}