Linux进程通信之文件

父子进程共享打开的文件描述符------使用文件完成进程间通信.

/***
 fork_share_fd.c
 ***/
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/wait.h>

int main(void)
{
    int fd1, fd2; pid_t pid;
    char buf[];
    char *str = "---------test for shared fd in parent child process-----\n";

    pid = fork();
    if (pid < ) {
        perror("fork error");
        exit();
    } else if (pid == ) {
        fd1 = open("test.txt", O_RDWR);
        if (fd1 < ) {
            perror("open error");
            exit();
        }
        write(fd1, str, strlen(str));
        printf("child wrote over...\n");

    } else {
        fd2 = open("test.txt", O_RDWR);
        if (fd2 < ) {
            perror("open error");
            exit();
        }
        sleep();                   //保证子进程写入数据

        int len = read(fd2, buf, sizeof(buf));
        write(STDOUT_FILENO, buf, len);

        wait(NULL);
    }

    return ;
}

运行结果：

ubuntu1604@ubuntu:~/wangqinghe/linux/20190806$ ./fork_share_fd

child wrote over...

---------test for shared fd in parent child process-----