lisp - Check if current Emacs buffer contains a string -

I have a buffer open in emacs. I need a task that will return t The current buffer has a string, otherwise it returns zero .

  (defun buffer-included - substrings (string) ...)  

It is careful to change where you are, or damage any match data.

  (defun buffer-containing-substring (string) (save-trip (save-match-data (goto-four (point-min)) (search-defined string zero t))) )