bug#50506: 28.0.50; display-line-numbers equivalent for linum-format?

[Eli Zaretskii]

> From: Michael Gallagher - NOAA Affiliate <michael.r.gallagher@noaa.gov>
> Date: Mon, 13 Sep 2021 12:17:09 -0600
> Cc: Lars Ingebrigtsen <larsi@gnus.org>, 50506@debbugs.gnu.org
> 
> Funny enough, that's *exactly* what I tried to do, but I ran into problems 
> getting the variable to display in
> customize-variable (a problem with what I put in cus-start.el?) and if I 
> manually used setq it didn't seem to
> get translated correctly by the way I coded the macro. 

I think if you look up all the pieces that handle
display-fill-column-indicator-character, both in C and in Lisp, you
will have your answers.  Feel free to ask specific questions if
something is still unclear after that.