Linux C 키 코드 읽 기

#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>
#include <sys/time.h>


struct timeval begin_time;
int reboot_done  = 0;

static void show_event(struct input_event* event)
{
    int current_time = event->time.tv_sec * 1000 + (int) event->time.tv_usec/1000;

    {
        if( event->value == 0 )
        {
            begin_time.tv_sec = 0;
            begin_time.tv_usec = 0;
            reboot_done  = 0;
                printf("%d %d %d [%d.%d]
", event->type, event->code, 
                        event->value, event->time.tv_sec,(int) event->time.tv_usec/1000 );


            printf("press release ! 
");
        }
        else if( event->value == 1 )
        {
            begin_time.tv_sec = event->time.tv_sec;
            begin_time.tv_usec = event->time.tv_usec;
                printf("%d %d %d [%d.%d]
", event->type, event->code, 
                        event->value, event->time.tv_sec,(int) event->time.tv_usec/1000 );


        }
        else if( event->value == 2 )
        {
                        if(event->time.tv_sec - begin_time.tv_sec >= 4)
            {
                if(event->time.tv_usec - begin_time.tv_usec >= 0)
                {
                    if(reboot_done == 0)
                    {
                        printf("%d %d %d [%d.%d]
", event->type, event->code, 
                                event->value, event->time.tv_sec,(int) event->time.tv_usec/1000 );

                        reboot_done = 1;
                        printf("press long then 4 s 
");
                    }
                }
            }
        }
    }

}

int main(int argc, char* argv[])
{
		struct input_event event = {{0}, 0};
		const char* file_name = argc == 2 ? argv[1] : "/dev/input/event0";
		int fd = open(file_name, O_RDWR);
		if(fd > 0)
		{

                do
				{
						int ret = read(fd, &event, sizeof(event));
						if(ret == sizeof(event))
						{
								show_event(&event);
						}
				}
				while(1);

				close(fd);
		}
        else
            printf("open filed %s 
", argv[1]);

		return 0;
}