In Emacs, what does this error mean? “Warning: cl package required at runtime”

The reason of this warning is a GNU policy which does not want a package cl to be used in Elisp. But it would be foolish as well to prohibit it completely. So they decided to show a warning.

You can find more information here


Just in case someone reads this on his quest for proper use of cl: The methods described here are now deprecated.

As least as of emacs 24, instead of cl you should use cl-lib or, if the macros suffice, cl-macs. These are new versions of cl that work with a clean namespace. E.g. instead of defun* you have cl-defun.

The old cl-package now is only for backward-compatibility and shouldn’t be used in new code.


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