c-toggle-hungry-state is an interactive compiled Lisp function in `cc-cmds.el'.

(c-toggle-hungry-state &optional ARG)

Toggle hungry-delete-key feature.
Optional numeric ARG, if supplied, turns on hungry-delete when
positive, turns it off when negative, and just toggles it when zero or
left out.

When the hungry-delete-key feature is enabled (indicated by "/h" on
the mode line after the mode name) the delete key gobbles all preceding
whitespace in one fell swoop.