Re: Changing value for fill-column

[Eli Zaretskii]

> Date: Sun, 28 Aug 2022 16:20:14 +0200 (CEST)
> From: wilnerthomas@tutanota.com
> Cc: help-gnu-emacs@gnu.org
> 
> > The doc string says:
> >
> >  Automatically becomes buffer-local when set.
> >
> > So you either need to set it in a mode-hook of each mode where you
> > want to change the default value, or you should use setq-default to
> > change the default value in all buffers.
> >
> I know how to add hook to major mode with a function but not using a variable.
> 
> (add-hook 'prog-mode-hook #'display-fill-column-indicator-mode)

You need to write a function that will both set fill-column and turn
on display-fill-column-indicator-mode.