5.2 Faces

CC Mode attempts to use the standard faces for programming languages in accordance with their intended purposes as far as possible. No extra faces are currently provided, with the exception of a replacement face c-invalid-face for emacsen that don’t provide font-lock-warning-face.

• Normal comments are fontified in font-lock-comment-face.
• Comments that are recognized as documentation (see Doc Comments) get font-lock-doc-face (Emacs) or font-lock-doc-string-face (XEmacs) if those faces exist. If they don’t then font-lock-comment-face is used.
• String and character literals are fontified in font-lock-string-face.
• Keywords are fontified with font-lock-keyword-face.
• font-lock-function-name-face is used for function names in declarations and definitions, and classes in those contexts. It’s also used for preprocessor defines with arguments.
• Variables in declarations and definitions, and other identifiers in such variable contexts, get font-lock-variable-name-face. It’s also used for preprocessor defines without arguments.
• Builtin constants are fontified in font-lock-constant-face if it exists, font-lock-reference-face otherwise. As opposed to the preceding two faces, this is used on the names in expressions, and it’s not used in declarations, even if there happen to be a ‘const’ in them somewhere.
• font-lock-type-face is put on types (both predefined and user defined) and classes in type contexts.
• Label identifiers get font-lock-constant-face if it exists, font-lock-reference-face otherwise.
• Name qualifiers and identifiers for scope constructs are fontified like labels.
• Special markup inside documentation comments are also fontified like labels.
• Preprocessor directives get font-lock-preprocessor-face if it exists (i.e. XEmacs). In Emacs they get font-lock-builtin-face or font-lock-reference-face, for lack of a closer equivalent.
• Some kinds of syntactic errors are fontified with font-lock-warning-face in Emacs. In older XEmacs versions there’s no corresponding standard face, so there a special c-invalid-face is used, which is defined to stand out sharply by default.

  Note that it’s not used for ‘#error’ or ‘#warning’ directives, since those aren’t syntactic errors in themselves.