测试阻塞读的app，包括select，poll

#include
#include
#include
#include
#include
#include
#include

int main(void)
{
   int fd_key,fd_ts, fd_led, fd_max;
   struct input_event event_key,event_ts;
   int dac_value;
   struct timeval select_timeout;
 
   fd_set readfds;

   select_timeout.tv_sec= 20;
   select_timeout.tv_usec = 0;  

   fd_key= open("/dev/input/event2", O_RDWR);
   fd_ts = open("/dev/input/event3", O_RDWR);

   if (fd_key>fd_ts)
       fd_max = fd_key;
   else
       fd_max = fd_ts;

   while(1)
   {
      FD_ZERO(&readfds);
      FD_SET(fd_key, &readfds);
      FD_SET(fd_ts, &readfds);
      
   select_timeout.tv_sec= 2;   
   select_timeout.tv_usec = 0;  
 
   select(fd_max + 1, &readfds, NULL, NULL, &select_timeout);
      if ( FD_ISSET(fd_key, &readfds))
         {
    printf("begin to read key\n");
           read(fd_key, &event_key, sizeof(struct input_event));
           printf("Udc Hotpluging:type=%d, code=%d, value=%d\n",event_key.type, event_key.code, event_key.value);
         }

      else  if(FD_ISSET(fd_ts, &readfds))
         {
 
    printf("begin to read touch screen\n");
           read(fd_ts, &event_ts, sizeof(struct input_event));
          
           printf("Power Charge value:type=%d, code=%d, value=%d\n",event_ts.type, event_ts.code, event_ts.value);
         }

      printf("select run again again\n");
   
    }
}