The options are:
-D name\^
0
-D name=def\^
-I dir\^ Same as in 8c "(1): add dir to the search for search 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 $objtype is read from the environment.
-V Print extra debugging information.
-P Do not insert `` #line '' directives into the output.
-+ Understand C++ comments.
-. Inhibit include search in the source's directory.
-i Print the list of directories searched when #include is found. Last listed are searched first.
In the absence of the -P option, the processed text output is sprinkled with lines that show the original input line numbering:
#line linenumber .L "ifile"The command reads the environment variable include and adds its (blank-separated) list of directories to the standard search path for #include directives. They are looked at before any directories specified with -I , which are looked at before the default directories.
The input language is as described in the ANSI C standard. The standard Plan 9 C compilers do not use cpp ; they contain their own simple but adequate preprocessor, so cpp is usually superfluous.
/sys/include directory for machine-independent include files
/$objtype/include directory for machine-dependent include files