the macro preprocessor for the C and C++ computer programming languages.
The C preprocessor or
cpp is the macro preprocessor for the c and c++ computer programming languages, although it is often used in conjunction with other languages. The preprocessor provides the ability for the inclusion of header files, macro expansions, conditional compilation, and line control.
The GNU CPP online manual describes the syntax and use of the C preprocessor.
The Pre-defined C/C++ Compiler Macros project lists pre-defined compiler macros that can be used to identify standards, compilers, operating systems and hardware architectures at compile-time.