I'm trying to add some functionality to someone else's package, and so I'd like to respect their patterns. Unfortunately, one of these patterns is to not use kbd.

I need to bind a function to C-S-b, but I can't figure out how. I know how to do this with a single modifier (e.g. "\S-b"), but I can't get it to work with multiple modifiers. I know I can just evaluate (kbd "C-S-b") and use its output ([33554434]), but I'd like something easier to read.

Here are a few things I've tried:

(define-key emacs-lisp-mode-map
  "\C-\S-b" 'test-command)
;;; Invalid modifier

(define-key emacs-lisp-mode-map
  [C-S-b] 'test-command)
;;; Does nothing

(define-key emacs-lisp-mode-map
  "\C-B" 'test-command)
;;; Binds C-b

1 Answer 1


You are missing a ? and two backslashes in the vector representation:

(global-set-key [?\C-\S-b] 'test-command)

The section on Key Sequences in the Elisp manual says:

Key sequences containing function keys, mouse button events, system events, or non-ASCII characters such as C-= or H-a cannot be represented as strings; they have to be represented as vectors.

In the vector representation, each element of the vector represents an input event, in its Lisp form. For example, the vector [?\C-x ?l] represents the key sequence C-x l.

And under Other Character Modifier Bits it says:

The Lisp syntax for the shift bit is \S-; thus, ?\C-\S-o or ?\C-\S-O represents the shifted-control-o character.


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