Eli Zaretskii <eliz@gnu.org> writes:

>> From: "Basil L. Contovounesios" <contovob@tcd.ie>
>> Date: Thu, 18 Mar 2021 13:41:04 +0000
>> Cc: juri linkov <juri@linkov.net>
>> 
>> The obvious band-aid is to check (fboundp 'tab-bar-height) in
>> frame-inner-height, but shouldn't we count 1 line when tab-bar-mode is
>> enabled even --without-x?  IOW, can/should tab-bar-height or similar be
>> defined regardless of HAVE_WINDOW_SYSTEM?  What's TRT here?
>
> TRT is to teach Emacs to return the tab-bar height on TTY frames as
> well.  But I don't think defining tab-bar-height on TTY frames is the
> right way: the tab-bar is always 1 line high on those frames, so we
> could simply use that hardcoded value instead of signaling an error, I
> think.

I'm not familiar with the tab bar, but I get the impression it's not
that simple.  IIUC no lines should be subtracted if tab-bar-mode is off,
and even if it's on, the tab bar can be hidden subject to tab-bar-show.
That's why I was wondering whether this logic can/should be packed into
a single place (whether Ftab_bar_height or other I don't know).

Is the following close to TRT?