text: #ifndef DATETIME_H
  #define DATETIME_H
  
  struct datetime {
    int hour;
    int min;
    int sec;
    int wday;
    int mday;
    int yday;
    int mon;
    int year;
  } ;
  
  typedef long datetime_sec;
  
  extern void datetime_tai();
  extern datetime_sec datetime_untai();
  
  #endif
  