DEL runs the command c-electric-backspace
  which is an interactive compiled Lisp function in `cc-cmds.el'.
It is bound to DEL.
(c-electric-backspace ARG)

Delete the preceding character or whitespace.
If `c-hungry-delete-key' is non-nil (indicated by "/h" on the mode
line) then all preceding whitespace is consumed.  If however a prefix
argument is supplied, or `c-hungry-delete-key' is nil, or point is
inside a literal then the function in the variable
`c-backspace-function' is called.