Re: c++-mode does not support C-h S?

[Eli Zaretskii]

> From: Sergey Organov <sorganov@gmail.com>
> Date: Mon, 06 Mar 2023 00:11:02 +0300
> 
> In a buffer with c++-mode major mode, pressing C-h S causes appearance
> of the prompt "Use symbol help mode: " in the minibuffer that, according
> to the manual, means c++-mode does not support info-lookup-symbol?:
> 
>  If you use C-h S in a major mode that does not support it, it asks you
>  to specify the symbol help mode. You should enter a command such as
>  c-mode that would select a major mode which C-h S does support.

If you type "c-mode RET" at the prompt, does the feature work then?

> How do I configure c++-mode to use c-mode to lookup symbols

Copy the two info-lookup-maybe-add-help blocks in info-look.el that
reference c-mode and make them reference c++-mode.

> and why it's not configured this way by default?

Because the _real_ documentation of C++ is usually not installed on
the end-user systems.