11 Customizing Indentation

The principal variable for customizing indentation is the style variable c-offsets-alist, which gives an offset (an indentation rule) for each syntactic symbol. Its structure and semantics are completely described in c-offsets-alist. The various ways you can set the variable, including the use of the CC Mode style system, are described in Configuration Basics and its sections, in particular Style Variables.

The simplest and most used kind of “offset” setting in c-offsets-alist is in terms of multiples of c-basic-offset:

User Option: c-basic-offset

This style variable holds the basic offset between indentation levels. Its factory default is 4, but all the built-in styles set it themselves, to some value between 2 (for gnu style) and 8 (for bsd, linux, and python styles).

The most flexible “offset” setting you can make in c-offsets-alist is a line-up function (or even a list of them), either one supplied by CC Mode (see Line-Up Functions) or one you write yourself (see Custom Line-Up Functions).

Finally, in Other Special Indentations you’ll find the tool of last resort: a hook which is called after a line has been indented. You can install functions here to make ad-hoc adjustments to any line’s indentation.