C preprocessor

This article has multiple issues. Please help improve it or discuss these issues on the talk page. (Learn how and when to remove these template messages) This article is written like a manual or guide. Please help rewrite this article and remove advice or instruction. (February 2013) This article includes a list of general references, but it lacks sufficient corresponding inline citations. Please help to improve this article by introducing more precise citations. (March 2015) (Learn how and when to remove this message) (Learn how and when to remove this message)

The C preprocessor is the macro preprocessor for several computer programming languages, such as C, Objective-C, C++, and a variety of Fortran languages. The preprocessor provides inclusion of header files, macro expansions, conditional compilation, and line control.

The language of preprocessor directives is only weakly related to the grammar of C, and so is sometimes used to process other kinds of text files.^[1]