/[NO]DIAGNOSTICS

  Controls whether the compiler creates a file containing compiler
  messages and diagnostic information.

  The default is /NODIAGNOSTICS.

  If you omit the file specification, the diagnostics file has the
  name of your source file and a file type of DIA.

  The diagnostics file is reserved for use with HP layered
  products such as, but not limited to, the Language Sensitive Editor
  (LSE).