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NAME

cpp - C language preprocessor

SYNOPSIS

cpp [ options ] [ input [ output ] ]

DESCRIPTION

cpp is the preprocessor for all C language dialects. It is a standalone version of the libpp(3) preprocessor library. The C dialect implemented by cpp is determined by probing cc(1) using probe(1). The path of the emulated compiler can be changed by the -D-X command line option.

If output is omitted then the standard output is written; if input is also omitted then the standard input is read. NOTE: this is an ancient, non-standard, non-intuitiive file operand syntax that is required by cc(1); use shell file name expansion at your peril.

cpp specific options are set by the -D- and -I- options.

OPTIONS

-C, --comments
Pass comments to the output. By default comments are omitted.
-D, --define=name[=value]
Define the macro name to have value; 1 is assumed if =value is omitted. If name begins with : then it is interpreted as a libpp(3) #pragma pp: statement; if name begins with % then it is interpreted as a libpp(3) # directive statement; if name begins with - or + then it is interpreted as a libpp(3) option; - turns the option on, + turns it off. Most options have a #pragma counterpart that is listed with the option definition. Right, this is ugly, but its the only portable way to pass options through cc(1) to cpp:
-D-C, pp:compatibility
Preprocess for K&R compatibility.
-D-Dlevel, pp:debug level
Set the debug trace level. Higher levels produce more output. Levels higher than 3 enabled only in -g compiled versions.
-D-Fname
Set the main input file name to name. This only affects error message and line sync output.
-D-H, pp:hosted
All directories are hosted; compatibility warning messages from hosted directory headers are suppressed.
-D-I, pp:cdir
All directories contain C headers; used only with -D-+.
-D-K, pp:keyargs
Enable the non-standard name=value macro argument mode.
-D-L[id], pp:lineid [id]
Set the line sync directive id to id or null if omitted.
-D-M, pp:nomultiple
Disable multiple include detection.
-D-P, pp:passthrough
Enable the non-standard passthrough mode; may be useful for processing non-C input.
-D-Q, pp:dump
Dump macro definitions to the output so that the output may be passed through cpp again. Used for generating precompiled headers.
-D-R, pp:transition
Enable the transition preprocessing mode. Used for compilers that can't make up their semantics between K&R and ISO.
-D-S, pp:strict
Enable strict preprocessing semantics and warnings. Works with any mode (compatibiliy, transition, or the default ISO).
-D-Ttest, pp:test test
Enable implementation specific test code according to test.
-D-W, pp:warn
Enable warnings in non-hosted files.
-D-X[cc]
Preprocess for the compiler cc which must be an executable path or an executable on $PATH.
-D-Y, pp:pedantic
Enable pedantic pp::warn warnings in non-hosted files.
-D-Z, pp:pool
Enable pool mode. See libpp(3).
-D-d
List canonicalized #define statements for non-predefined macros in the output.
-D-m
List canonicalized #define statements for all macros. All other output is disabled.
-D-+, pp:plusplus
Preprocess for the C++ dialect.
-I, --include[=directory]
Append directory to the list of directories searched for #include files. If directory is - then: (1) -I directories before -I- are searched only for "..." include files; (2) -I directories after -I- are searched for "..." and <...> include files; (3) the directory . is searched only if it is explicitly specified by a -I option.
-I-Cdirectory, pp:cdir directory
Mark directory as a C header directory. Used with pp:plusplus.
-I-D[file]
Read the default probe(1) definitions from file, or ignore the default definitions if file is omitted.
-I-Hdirectory, pp:hostdir directory
Mark directory as a hosted directory. Headers from hosted directories have compatibility warnings disabled.
-I-Iheader, pp:ignore header
Add header to the list of ignored headers.
-I-Mfile
file contains a sequence of header [= "map" ] lines, where header is either <name > or "name", and "map" is an explicit binding for header. header is ignored if = "map" is omitted.
-I-Rfile
Include file but do not emit text or line syncs.
-I-Sdirectory
Add directory to the default standard include directory list.
-I-Tfile
Include file and emit text to the output file.
The option value may be omitted.
-M, --dependencies
Generate make(1) dependencies. Not needed with nmake(1). -M may be followed by optional flags to change dependency output styles:
D
Generate dependencies in a separate .d file. Preprocessed output is still written to output, or the standard output if output is omitted.
G
Generate missing dependencies too.
M
Only generate local header dependencies; hosted headers are omitted. Note that hosted headers are determined by -I-H and the pp:hosted and pp:hostdir pragmas; no special distiction is made between "" and <> include styles.
-P, --sync
Emit line syncs. On by default; -P means --nosync.
-U, --undefine=name
Remove the definition for the macro name.
-A, --assert=assertion
Enter the assertion via #assert for system V compatibility.
-E, --preprocess
Ignored for compatibility with ancient compilers.
-H, --include-reference
Emit #include file paths on the standard error, one per line, indented to show nesting.
-T[length]
If not gcc(1) then truncate identifiers to length characters for compatibility with old AT&T (I guess only Lucent needs them now) compilers. The option value may be omitted.
-V, --version
Emit the libpp(3) version.
-X, --argmode
Enable name=value macro arguments for easel(1) compatibility.
-Y, --standard=directory
Add directory to the list searched for #include <...> files.

SEE ALSO

cc(1), gcc(1), libpp(3)

IMPLEMENTATION

version
cpp (AT&T Research) 2007-03-11
author
Glenn Fowler <gsf@research.att.com>
copyright
Copyright © 1986-2008 AT&T Intellectual Property
license
http://www.opensource.org/licenses/cpl1.0.txt