c-multiline-string-start-char

c-multiline-string-start-char is a variable defined in `cc-engine.el'.
Its value is

nil

• Automatically becomes buffer-local when set.

Documentation:
Set if the language supports multiline string literals without escaped
newlines. If t, all string literals are multiline. If a character,
only literals where the open quote is immediately preceded by that
literal are multiline.