Variable: c-line-comment-starter
c-line-comment-starter is a buffer-local variable defined in
cc-engine.el.gz.
Documentation
String that starts line comments, or nil if such don't exist.
Line comments are always terminated by newlines. At least one of
c-block-comment-starter and this one is assumed to be set.
Note that it's currently not enough to set this to support a new comment style. Other stuff like the syntax table must also be set up properly.
Source Code
;; Defined in /usr/src/emacs/lisp/progmodes/cc-engine.el.gz
(c-declare-lang-variables)