When editing Emacs Lisp code, you can use the commands C-h f
describe-function) and C-h v (
to view the built-in documentation for the Lisp functions and
variables that you want to use. See Name Help.
ElDoc is a buffer-local minor mode that helps with looking up Lisp documentation. When it is enabled, the echo area displays some useful information whenever there is a Lisp function or variable at point; for a function, it shows the argument list, and for a variable it shows the first line of the variable’s documentation string. To toggle ElDoc mode, type M-x eldoc-mode. There’s also a Global ElDoc mode, which is turned on by default, and affects buffers whose major mode sets the variables described below. Use M-x global-eldoc-mode to turn it off globally.
These variables can be used to configure ElDoc mode:
This variable holds the function which is used to retrieve
documentation for the item at point from the functions in the hook
eldoc-documentation-functions. By default,
eldoc-documentation-strategy returns the first documentation
string produced by the
eldoc-documentation-functions hook, but
it may be customized to compose those functions’ results in other
This abnormal hook holds documentation functions. It acts as a collection of backends for ElDoc. This is what modes should use to register their documentation functions with ElDoc.
nil (the default), display a verbose message about how
to view a complete documentation (if it has been truncated in the echo
nil, just mark truncated messages with ‘...’.