VMS Help BASIC, /LINES  *Conan The Librarian (sorry for the slow response - running on an old VAX)

   The /LINES qualifier makes line number information available for  the  ERL
   function, and the BASIC error reporter.

   The format of the /LINES qualifier is as follows:

      /[NO]LINES

   If your program contains a RESUME statement with no target or a  reference
   to  the  error-handling  function  ERL,  VAX  BASIC overrides the /NOLINES
   qualifier and signals "ERL overrides NOLINE" or "RESUME overrides NOLINE".
   Note  that  the  BASIC  error  reporting facility is separate from that of
   system traceback.

   The /NOLINES qualifier causes line number information  to  be  unavailable
   for  the ERL function, the RESUME statement (with no target) and the BASIC
   error reporter.  If you specify /NOLINES, your program runs faster and the
   program size is reduced (this eliminates five bytes of code and four bytes
   of data for each program line number).  However, if you specify  /NOLINES,
   the following restrictions occur:

    o  You cannot use RESUME without a line number.
    o  You cannot use the ERL function.
    o  No BASIC line number is given in run-time error messages.

   This option should be used only for programs  that  have  been  thoroughly
   debugged and whose execution time is critical.

   The default is /LINES.