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The variables that CC Mode’s style system control are called style variables. Note that style variables are ordinary Lisp variables, which the style system initializes; you can change their values at any time (e.g. in a hook function). The style system can also set other variables, to some extent. See Styles.
Style variables are handled specially in several ways:
c-style-variables-are-local-p
to nil
before CC Mode is
initialized.
set-from-style
. When the
style system initializes a buffer-local copy of a style variable for a
CC Mode buffer, if its global binding is still that symbol then it
will be set from the current style. Otherwise it will retain its
global default17. This
“otherwise” happens, for example, when you’ve set the variable with
setq
at the top level of your .emacs (see Config Basics).
c-offsets-alist
(see c-offsets-alist) is
an association list with an element for each syntactic symbol. It’s
handled a little differently from the other style variables. It’s
default global binding is the empty list nil
, rather than
set-from-style
. Before the style system is initialized, you
can add individual elements to c-offsets-alist
by calling
c-set-offset
(see c-offsets-alist) just like you would set
other style variables with setq
. Those elements will then
prevail when the style system later initializes a buffer-local copy of
c-offsets-alist
.
c-special-indent-hook
is also handled in a
special way. Styles can only add functions to this hook, not remove
them, so any global settings you put on it are always
preserved18. The value
you give this variable in a style definition can be either a function
or a list of functions.
user
style when the style system is first initialized.
See Built-in Styles, for details.
The style variables are:
c-indent-comment-alist
,
c-indent-comments-syntactically-p
(see Indentation Commands);
c-doc-comment-style
(see Doc Comments);
c-block-comment-prefix
, c-comment-prefix-regexp
(see Custom Filling and Breaking);
c-hanging-braces-alist
(see Hanging Braces);
c-hanging-colons-alist
(see Hanging Colons);
c-hanging-semi&comma-criteria
(see Hanging Semicolons and Commas);
c-cleanup-list
(see Clean-ups);
c-basic-offset
(see Customizing Indentation);
c-offsets-alist
(see c-offsets-alist);
c-comment-only-line-offset
(see Comment Line-Up);
c-special-indent-hook
, c-label-minimum-indentation
(see Other Indentation);
c-backslash-column
, c-backslash-max-column
(see Custom Macros).
This is a big change from versions of
CC Mode earlier than 5.26, where such settings would get overridden
by the style system unless special precautions were taken. That was
changed since it was counterintuitive and confusing, especially to
novice users. If your configuration depends on the old overriding
behavior, you can set the variable
c-old-style-variable-behavior
to non-nil
.
This did not change in version 5.26.
Next: Styles, Previous: CC Hooks, Up: Config Basics [Index]