求教！！ linux read函数 出错? 400 报错

求教！！ linux read函数 出错? 400 报错

请求懂的人帮忙看一下！

read input子系统中的event2文件，出错很奇怪

代码如下：有疑问的部分用红色标注

#include <stdio.h>
#include <stdlib.h>
#include <linux/input.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>

static void show_event(struct input_event* event)
{
        printf("%d %d %d/n", event->type, event->code, event->value);

        return;
}

int main()
{
        struct input_event event;
        printf("sizeof of input_event:%d\n",sizeof(event));  //打印16

        const char *file_name = "/dev/input/event2";

        int fd = open(file_name, O_RDONLY);
        if(fd > 0)
        {
                while(1)
                {
                        printf("in while\n");   //可以被执行到
                        int ret = read(fd, &event, sizeof(event)); //将sizeof(event) 换成小于16的数字，就可以执行到下一条语句
                        printf("ret: %d\n",ret);  //不被执行了

                        if(ret == sizeof(event))
                        {
    printf("before show event\n");
                                show_event(&event);
                        }
                        else
                        {
    printf("in else!\n");
                                break;
                        }
                }
                close(fd);
        }

        return 0;
}

谢谢~~