bug#57693: 29.0.50; Is there a more reliable version of `char-displayable-p'?

[Stefan Kangas]

Eli Zaretskii <eliz@gnu.org> writes:

> Something like what?  If you want to suggest some specific function,
> please show the proposed code, and let's take it from there.
> Otherwise, this bug discussion was long and considered several issues,
> and it is hard to know what you have in mind.

The code is here:

    https://debbugs.gnu.org/cgi/bugreport.cgi?bug=57693#71

>> I can see a need for it in many more places.  For example, I'm looking
>> into improving the header-line-format in calc-mode with some Unicode
>> characters instead of a simple en dash (i.e. "‒" instead of "-").
>
> And what is the problem with using char-displayable-p in that case?

My concern is that `char-displayable-p' will return t even if the
character is not displayable.