cpp — C Language Preprocessor
/usr/ccs/lib/cpp [-BCHMpPRT] [-undef] [-Dname] [-Dname=def] [-Idirectory] [-Uname] [-Ydirectory] [input-file [output-file]]
cpp is the C language preprocessor. It is invoked as the first pass of any C compilation started with the cc(1B) command; however, you can also use cpp as a first-pass preprocessor for other Sun compilers.
Although you can use cpp as a macro processor, it is not normally recommended because its output is designed to be acceptable as input to a compiler's second pass. The preferred way to invoke cpp is through the cc(1B) command or some other compilation command. ...