The valid format for the mfpp command is:
mfpp [–ipath dir][-{isuffix|x} suffix] [–pp outfile]infile
where dir is a directory name, suffix defines a string to be appended to any unquoted filename in a %INCLUDE statement, infile specifies a source filename, and outfile specifies an output filename. At least one input file must be specified.
The preprocessor input is a file containing an Open PL/I source module, possibly including Open PL/I Macro Preprocessor statements. The preprocessor output is an Open PL/I source module containing no further preprocessor statements, but with the source code modified according to the semantics of the preprocessor statements that were encountered in the input file.