ref: c0176a50519a4a978f1d59ef78bd1c9fcfa7f66f
dir: /sys/man/1/cpp/
.TH CPP 1 .SH NAME cpp \- C language preprocessor .SH SYNOPSIS .B cpp [ .I option ... ] [ .I ifile [ .I ofile ] ] .SH DESCRIPTION .I Cpp\^ interprets ANSI C preprocessor directives and does macro substitution. The input .I ifile and output .I ofile default to standard input and standard output respectively. .PP The 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 dir to the search for .CW search directives. .PD .TP .B -M Generate no output except a list of include files in a form suitable for specifying dependencies to .IR mk (1). Use twice to list files in angle brackets. .TP .B -N Turn off default include directories. All must be specified with .BR -I , or in the environment variable .BR include . Without this option, .B /$objtype/include and .B /sys/include are used as the last two searched directories for include directives, where .B $objtype is read from the environment. .TP .B -V Print extra debugging information. .TP .B -P Do not insert .RB `` #line '' directives into the output. .TP .B -+ Understand C++ comments. .TP .B -. Inhibit include search in the source's directory. .TP .B -i Print the list of directories searched when .I #include is found. Last listed are searched first. .PD .PP In the absence of the .B -P option, the processed text output is sprinkled with lines that show the original input line numbering: .IP .B #line .I linenumber .L "\fIifile\fP" .PP The command reads the environment variable .IR include and adds its (blank-separated) list of directories to the standard search path for .CW #include directives. They are looked at before any directories specified with .BR -I , which are looked at before the default directories. .PP The input language is as described in the ANSI C standard. The standard Plan 9 C compilers do not use .IR cpp ; they contain their own simple but adequate preprocessor, so .I cpp is usually superfluous. .SH FILES .TF /objtype/include .TP .B /sys/include directory for machine-independent include files .TP .B /$objtype/include directory for machine-dependent include files .SH SOURCE .B /sys/src/cmd/cpp .SH SEE ALSO .IR 2c (1)