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

   The /DIAGNOSTICS qualifier controls the creation  of  a  diagnostics  file
   containing  compiler  messages  and  diagnostic information for use by the
   Compaq Language-Sensitive Editor (LSE).

   The format of the /DIAGNOSTICS qualifier is as follows:

      /[NO]DIAGNOSTICS[=file-spec]

   LSE uses the diagnostics file to display diagnostic error messages and  to
   position the cursor on the line and column where a source error exists.

   If you do not supply a file specification with the /DIAGNOSTICS qualifier,
   the  diagnostics  file  has the same name as its corresponding source file
   and a default file type of .DIA.  All other file specification  attributes
   depend on the placement of the qualifier in the command.

   The default is /NODIAGNOSTICS.