/sys$common/syshlp/helplib.hlb PASCAL, Input Output, General, CLOSE, User Action  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  The 'user_action' is a routine name that Compaq Pascal calls  to
  close  the file.  You can use a user-action routine to close the
  file using environment-specific capabilities.