A program invoked by variouScompilerS to proceSS code before compilation. For example, the C preproceSSor, cpp, handleS textual macroSubStitution, {conditional compilation} and incluSion of other fileS. A preproceSSor may be uSed to tranSform a program into a Simpler language, e.g. to tranSform C++ into C. (1994-11-09)