// 写进程
int main(int argc, char **argv) {
    char filename[] = "/tmp/my_fifo";
    if (mkfifo(filename, 0777) < 0) {
        perror("mkfifo error");
        exit(1);
    }
    int fd = open(filename, O_WRONLY);
    char buffer[128] = "hello world";
    write(fd, buffer, strlen(buffer));
    printf("write done\n");
    return 0;
}

// 读进程
int main(int argc, char **argv) {
    char filename[] = "/tmp/my_fifo";
    int fd = open(filename, O_RDONLY);
    char buffer[128];
    int n = read(fd, buffer, 128);
    buffer[n] = ‘\0‘;
    printf("input is : %s\n", buffer);
    return 0;
}