c-common-init is a compiled Lisp function in `cc-mode.el'.

(c-common-init &optional MODE)

Common initialization for all CC Mode modes.
In addition to the work done by `c-basic-common-init' and
`c-font-lock-init', this function sets up various other things as
customary in CC Mode modes but which aren't strictly necessary for CC
Mode to operate correctly.

MODE is the symbol for the mode to initialize, like 'c-mode. See
`c-basic-common-init' for details. It's only optional to be
compatible with old code; callers should always specify it.