Emacs Lisp: Check If a function/variable is Defined
This page shows you how to check if a {function, variable} is defined, or if a “feature” is loaded.
Check If Function is Defined
;; check if a function is defined (fboundp 'info) ; t (fboundp 'setq) ; t (fboundp 'xyz) ; nil
Technically,
fboundp
check a Symbol's function cell.
Check If Variable is Defined
;; check if a variable is defined (boundp 'auto-mode-alist) ; t (boundp 'default-input-method) ; t (boundp 'nil) ; t (boundp 'xyz) ; nil
Technically,
boundp
checks a Symbol's value cell.
Check Feature
;; check if a “feature” (package) has been loaded (featurep 'ibuffer)