if(定時條件) 
   {       
      //Timeout to run first time        
      tick.it_value.tv_sec = 10;       
      tick.it_value.tv_usec = 0;       
     //After first, the Interval time for clock       
      tick.it_interval.tv_sec = 10;
      tick.it_interval.tv_usec = 0;      
      if(setitimer(ITIMER_REAL, &tick, NULL) < 0)//set      
   }
   if(取消定時條件)
   {      
      //Timeout to run first time;        
      tick.it_value.tv_sec = 0;        
      tick.it_value.tv_usec = 0;       
     //After first, the Interval time for clock        
      tick.it_interval.tv_sec = 0;
      tick.it_interval.tv_usec = 0;        
      if(setitimer(ITIMER_REAL, &tick, NULL) < 0) 
   }
  return 0; 
}