bug#33829: 26.1; Unicode codepoint 177, PLUS-MINUS SIGN doesn't insert

[Eli Zaretskii]

> Date: Fri, 21 Dec 2018 08:50:51 -0800 (PST)
> From: Drew Adams <drew.adams@oracle.com>
> 
> See https://emacs.stackexchange.com/q/46713/105
> 
> emacs -Q
> 
> (global-set-key (kbd "C-o") "±")
> 
> Then try `C-o'.  Instead of inserting the char you get `C-u 1-' in the
> minibuffer.  Emacs seems to be interpreting `C-o' as a partial numeric
> prefix arg.

No, it interprets ±, which is a single byte with the 8th bit set, as a
meta character.

(I wonder why you expected this to work even.)

> But this works fine:
> 
> (global-set-key (kbd "C-o") "☬") to insert ☬.

Because ☬ doesn't fit in a single byte.