CPP(1)

NAME

cpp − C language preprocessor

SYNOPSIS

cpp [ option ... ] [ ifile [ ofile ] ]

DESCRIPTION

Cpp interprets ANSI C preprocessor directives and does macro substitution. The input ifile and output ofile default to standard input and standard output respectively.

The options are:

-Dname

-Dname=def

-Idir Same as in 2c(1): add dir to the search for directives.

-M Generate no output except a list of include files in a form suitable for specifying dependencies to mk(1). Use twice to list files in angle brackets.

-N Turn off default include directories. All must be specified with -I, or in the environment variable include. Without this option, /$objtype/include and /sys/include are used as the last two searched directories for include directives, where $objtype is read from the environment.

-V Print extra debugging information.

-P Do not insert “#line” directives into the output.

-+ Understand C++ comments.

-i Print the list of directories searched when #include is found. Last listed are searched first.

In the absence of the -P option, the processed text output is sprinkled with lines that show the original input line numbering:

#line linenumber "ifile"

The command reads the environment variable include and adds its (blank-separated) list of directories to the standard search path for directives. They are looked at before any directories specified with -I, which are looked at before the default directories.

The input language is as described in the ANSI C standard. The standard Plan 9 C compilers do not use cpp; they contain their own simple but adequate preprocessor, so cpp is usually superfluous.

FILES

/sys/include directory for machine-independent include files

/$objtype/include
directory for machine-dependent include files

SOURCE

/sys/src/cmd/cpp

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