UNSAFE INTERFACEUdir ; FROM Ctypes IMPORT const_char_star, int; TYPE DIR_star = ADDRESS; (* opaque *) struct_dirent_star = ADDRESS; <*EXTERNAL Udir__opendir*> PROCEDURE opendir (filename: const_char_star): DIR_star; <*EXTERNAL Udir__readdir*> PROCEDURE readdir(dirp: DIR_star): struct_dirent_star; <*EXTERNAL Udir__closedir*> PROCEDURE closedir(dirp: DIR_star): int; END Udir.