Library /sys$common/syshlp/basichelp.hlb Compile time errors, ILLMULOPT  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  ERROR - The OPTIONAL clause  was  specified  more  than  once  in  the
  EXTERNAL  statement for a single SUB or FUNCTION.  This is not allowed
  because  OPTIONAL  implies  that  all  parameters  following  it   are
  optional.  Fix the EXTERNAL statement so that it has only one OPTIONAL
  clause per SUB or FUNCTION.