Variables for C Indentation

This section describes additional variables which control the indentation behavior of C mode and related mode.

c-offsets-alist

Association list of syntactic symbols and their indentation offsets. See section Changing Indentation Style, for details.

c-offsets-alist-default

Default settings for the offsets of the syntactic symbols. See section Changing Indentation Style.

c-style-alist

Variable for specifying styles of indentation; see below.

c-basic-offset

Amount of basic offset used by + and - symbols in c-offsets-alist.

c-recognize-knr-p

If this variable is non-nil, C mode and Objective C mode recognize K&R constructs. This variable is needed because of ambiguities in C syntax that make recognition of K&R constructs problematic and slow. If you always use ANSI C prototype syntax, set this variable to nil to speed up C indentation. This variable is nil by default in C++ mode, and t by default in C mode and Objective C mode.

c-special-indent-hook

Hook for user-defined special indentation adjustments. This hook is called after a line is indented by C mode and related modes.

The variable c-style-alist specifies the predefined indentation styles. Each element has form (name variable-setting...), where name is the name of the style. Each variable-setting has the form (variable . value); variable is one of the customization variables used by C mode, and value is the value for that variable when using the selected style.

When variable is c-offsets-alist, that is a special case: value is appended to the front of the value of c-offsets-alist instead of replacing that value outright. Therefore, it is not necessary for value to specify each and every syntactic symbol--only those for which the style differs from the default.

The indentation of lines containing only comments is also affected by the variable c-comment-only-line-offset (see section Comments in C Modes).