Decus cpp

from The Free On-line Dictionary of Computing (8 July 2008)

Decus cpp

   An almost-{ANSI C} {preprocessor} by Martin Minow.  It is
   shipped with {X11R5} (contrib/util/cpp) because some systems
   don't have a working {cpp}.

   It runs on {VMS} ({Vax C}, {Decus C}), {RSX-11M}, {RSTS/E},
   {P/OS}, {RT11}, {A/UX} and {Apollo Domain}/IX 9.6 and is
   highly portable.

   (1994-11-03)