/sys$common/syshlp/helplib.hlb FORTRAN, /WARNINGS, DECLARATIONS  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  Controls whether the compiler issues diagnostic messages
  for any untyped data items used in the program.  This option acts
  as an external IMPLICIT NONE declaration.  See your language
  reference manual for more information on IMPLICIT NONE.