Variable: change-major-mode-hook
change-major-mode-hook is a variable defined in buffer.c.
Value
(c-leave-cc-mode-mode
mode-local-on-major-mode-change)
Documentation
Normal hook run before changing the major mode of a buffer.
The function kill-all-local-variables runs this before doing anything else.
Probably introduced at or before Emacs version 19.23.
Source Code
// Defined in /usr/src/emacs/src/buffer.c
DEFVAR_LISP ("change-major-mode-hook", Vchange_major_mode_hook,
doc: /* Normal hook run before changing the major mode of a buffer.
The function `kill-all-local-variables' runs this before doing anything else. */);