Re: Why the C-M-<keys> is invalid in my emacs?

[Robert Thorpe]

Navy Cheng <navych@126.com> writes:
> I use Debian 8 and Xfce Desktop Environment. 'M-' is OK and 'C-M-' is OK in 
> other
> software execpt emacs.

That's odd.  Have you tried "emacs -q"?  Do C-M-something keys work in
unconfigured Emacs?

BR,
Robert Thorpe