Variable: auto-fill-function
auto-fill-function is a buffer-local variable defined in buffer.c.
Documentation
Function called (if non-nil) to perform auto-fill.
It is called after self-inserting any character specified in
the auto-fill-chars table.
NOTE: This variable is not a hook;
its value may not be a list of functions.
Probably introduced at or before Emacs version 19.29.
Source Code
// Defined in /usr/src/emacs/src/buffer.c
DEFVAR_PER_BUFFER ("auto-fill-function", &BVAR (current_buffer, auto_fill_function),
Qnil,
doc: /* Function called (if non-nil) to perform auto-fill.
It is called after self-inserting any character specified in
the `auto-fill-chars' table.
NOTE: This variable is not a hook;
its value may not be a list of functions. */);