VMS Help PASCAL, Predeclared Routines, Char Strng, STATUSV  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  The STATUSV function returns an integer value that specifies the
  status  of the last READV or WRITEV completed.  It does not have
  any parameters.

  Note that  if  you  have  an  asynchronous  trap  (AST)  routine
  condition  handler  written  in your program that uses READV and
  WRITEV, the call of STATUSV in your main program may not  return
  the  results  you  expected  if  an  AST  occurred  between  the
  READV/WRITEV and STATUS.