Variable: search-upper-case

search-upper-case is a customizable variable defined in isearch.el.gz.

Value

not-yanks

Documentation

If non-nil, upper case chars disable case fold searching.

That is, upper and lower case chars must match exactly. This applies no matter where the chars come from, but does not apply to chars in regexps that are prefixed with \. If this value is not-yanks, text yanked into the search string in Isearch mode is always downcased.

View in manual

Probably introduced at or before Emacs version 28.1.

Source Code

;; Defined in /usr/src/emacs/lisp/isearch.el.gz
(defcustom search-upper-case 'not-yanks
  "If non-nil, upper case chars disable case fold searching.
That is, upper and lower case chars must match exactly.
This applies no matter where the chars come from, but does not
apply to chars in regexps that are prefixed with `\\'.
If this value is `not-yanks', text yanked into the search string
in Isearch mode is always downcased."
  :type '(choice (const :tag "off" nil)
		 (const not-yanks)
		 (other :tag "on" t)))