Alan Mackenzie <acm@muc.de> schrieb am Fr., 17. Nov. 2017 um 20:00 Uhr:

> In article <mailman.3878.1510925890.27995.bug-gnu-emacs@gnu.org> you
> wrote:
>
> > GCC uses .mm or .M for Objective-C++,
> > cf. https://gcc.gnu.org/onlinedocs/gcc-7.2.0/gcc/Overall-Options.html.
> > However, neither `auto-mode-alist' nor `cc-other-file-alist' contain
> > these file extensions.
>
> I don't think there's an Objective-C++ mode out there in the wild.  So
> what existing mode should be used for *.mm and *.M?  Is that mode a good
> enough fit to be able, in good conscience, to use it for Obj-C++?
>

According to https://www.emacswiki.org/emacs/ObjectiveCMode#toc2 objc-mode
is the most appropriate mode for now, until a true objc++-mode is added.