cpp-4.8

cpp-4.8 [-option...] [input-file] [-o output-file]

-D name[=defn]
    Predefine name as a macro, with optional defn (default 1)

-U name
    Cancel predefined or command-line macro name

-I dir
    Add dir to include search path end

-iquote dir
    Add dir to quote include path

-isystem dir
    Add dir to system include path

-idirafter dir
    Overlay dir after standard paths

-include file
    Process file as if #include "file" at start

-imacros file
    Process file for macro definitions only

-undef
    Do not predefine system-specific macros

-nostdinc
    Ignore standard include directories

-o file
    Write output to file instead of stdout

-M
    Generate dependency makefile rules (non-phony targets)

-MM
    Like -M, ignore system header dependencies

-MD file
    Like -M but output to file

-MG
    Generate phantom dependencies for missing headers

-MP
    Add phony targets to dependency output

-MT target
    Specify target in dependency output

-MQ target
    Like -MT but quote target for make

-P
    Disable linemarkers in output

-C
    Preserve comments in output

-CC
    Preserve comments even in system headers

-w
    Suppress all warnings

-W,[]
    Enable specific warnings

-x language
    Specify input language (c|c++|objective-c)

-ansi
    Support only ISO Standard C syntax

-traditional-cpp
    Enable traditional C preprocessor behavior

-dM
    Dump all predefined macros

-H
    Print include file path hierarchy

The cpp-4.8 command is the GNU C Preprocessor from GCC 4.8, used to expand macros, process include directives, and handle conditional compilation in C, C++, and Objective-C source code. It transforms source files into preprocessed output suitable for the compiler.

Invoked standalone or via compiler drivers like gcc-4.8 -E, it supports #define, #include, #ifdef, #if, #error, and more. Key features include directory include paths, macro definitions/undefinitions, and warning controls. This version aligns with GCC 4.8's support for ISO C90/C99/C11 (partial), C++98/C++11 (partial), and GNU extensions.

Common uses: generating dependency files for make, inspecting macro expansions, or porting code. Output defaults to stdout unless redirected with -o. It searches system and user-specified include paths, with -nostdinc to disable standards.

GCC 4.8's cpp improves diagnostics, trigraph handling, and performance over prior versions, but lacks modern C++20/C2x features.

Version-specific to GCC 4.8 (2013); may conflict with newer GCC versions. Not installed by default on modern distros. Use gcc-4.8 -E for equivalent. Limited C11/C++11 support; no modules or modern attributes.

Often used indirectly: gcc-4.8 -E source.c -o source.i. Standalone for Makefile deps or macro inspection.

ISO C90 standard; partial C99/C11. GNU extensions via -std=gnu (default). Use -ansi for strict mode.

Preprocessed code with linemarkers (#line). Use -P to remove. Comments stripped unless -C.

Introduced with GCC 4.8.0 (May 23, 2013). Enhanced C++11 diagnostics, OpenMP 4.0 support, and LTO improvements. Widely used until GCC 5+ adoption; still available via compat packages in Ubuntu/Debian.

gcc-4.8(1), g++-4.8(1), cpp(1), m4(1)