.TH CPP 1.SH NAMEcpp \- C language preprocessor.SH SYNOPSIS.B cpp[.I option ...][.I ifile[.I ofile]].SH DESCRIPTION.I Cpp\^interprets ANSI C preprocessor directivesand does macro substitution.The input.I ifileand output.I ofiledefault to standard input and standard output respectively..PPThe options are:.TP.BI -D name\^.PD 0.TP.BI -D name=def\^.TP.BI -I dir\^Same as in.IR 2c "(1): add.I dirto the search for.CW searchdirectives..PD.TP.B -MGenerate no output except a list of include filesin a form suitable for specifying dependencies to.IR mk (1).Use twice to list files in angle brackets..TP.B -NTurn off default include directories.  All must bespecified with.BR -I ,or in the environment variable.BR include .Without this option,.B /$objtype/includeand.B /sys/includeare used as the last two searched directories for include directives,where.B $objtypeis read from the environment..TP.B -VPrint extra debugging information..TP.B -PDo not insert.RB `` #line ''directives into the output..TP.B -+Understand C++ comments..TP.B -.Inhibit include search in the source's directory..TP.B -iPrint the list of directories searched when.I #includeis found.Last listed are searched first..PD.PPIn the absence of the.B -Poption, the processed text output is sprinkledwith lines that show the original input line numbering:.IP.B #line.I linenumber.L"\fIifile\fP".PPThe command reads the environment variable.IR includeand adds its (blank-separated) list of directories tothe standard search path for.CW #includedirectives.  They are looked at before any directories specified with.BR -I ,which are looked at before the default directories..PPThe input language is as described in the ANSI C standard.The standard Plan 9 C compilers do not use.IR cpp ;they contain their own simple but adequate preprocessor, so.I cppis usually superfluous..SH FILES.TF /objtype/include.TP.B /sys/includedirectory for machine-independent include files.TP.B /$objtype/includedirectory for machine-dependent include files.SH SOURCE.B /sys/src/cmd/cpp.SH SEE ALSO.IR 2c (1)