Variable: display-fill-column-indicator

display-fill-column-indicator is a customizable and buffer-local variable defined in xdisp.c.

Documentation

Non-nil means display the fill column indicator.

If you set this non-nil, make sure display-fill-column-indicator-character is also non-nil. See Info node (emacs)Displaying Boundaries for details.

This variable was added, or its default value changed, in Emacs 27.1.

Probably introduced at or before Emacs version 27.1.

Source Code

// Defined in /usr/src/emacs/src/xdisp.c
  DEFVAR_BOOL ("display-fill-column-indicator", display_fill_column_indicator,
    doc: /* Non-nil means display the fill column indicator.
If you set this non-nil, make sure `display-fill-column-indicator-character'
is also non-nil.
See Info node `Displaying Boundaries' for details.  */);