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

  ERROR - A  DEF  function  reference  contains  a  null  argument,  for
  example,  FNA(1,,2)  Specify  all  arguments  when  referencing  a DEF
  function.