The #module directive is retained for compatibility with VAX C and
  is supported only when running the HP C compiler in VAX C mode
  (/STANDARD=VAXC).  See also the ANSI C equivalent #pragma module
  directive.

  The #module directive passes information about an object module to
  the compiler.

  The #module directive can have one of the following forms:

       #module identifier identifier
       #module identifier string

  The first argument of the directive is an HP C identifier or macro
  that resolves to an identifier.  It gives the system-recognized
  (for example, internally recognized by the debugger and the
  librarian) name of the module; the object file name remains the
  same.  The second argument specifies the optional identification
  that appears on listings.  This may be either a VAX C identifier, a
  character-string constant with no more than 31 characters, or a
  macro that resolves to one of these.

  There can be only one #module directive per compilation.  It can
  appear anywhere before the C language text.