Stefan Monnier <monnier@iro.umontreal.ca> schrieb am Mon Feb 09 2015 at
5:23:09 AM:

> > It’s a nice feature but be aware that most DE-specific X-based
> > terminal emulators (GNOME, Xfce, Konsole, …) do not implement it and
> > still advertise themselves as TERM=xterm[-256color].
>
> Right, the code needs to be able to handle the situation where the
> underlying terminal emulator doesn't support the feature.
>
> There are typically 2 situations:
> - the terminal emulator just ignores the special codes we send, so we
>   can happily delude ourselves into thinking they always work.
> - we check the terminal version info before enabling/using the feature
>   (see xterm--version-handler in lisp/xterm.el).
>
> It seems the first option won't work here, since we may send large
> chunks of text as clipboard contents, which are unlikely to be
> silently ignored.
>
>
>

http://invisible-island.net/xterm/xterm.log.html#xterm_203 says "add
experimental option to allow applications to get or set the selection data
as a BASE64 string (adapted from patch by Joe Allen)." I assume this is the
OSC 52 functionality, so setting 203 as the minimum requirement sounds like
a reasonable choice. On my Ubuntu 14.04 box I found the following version
strings reported:

hterm: "0;256;0"
xterm: "41;297;0"
gnome-terminal: "1;3409;0"

gnome-terminal gets adjusted to 200, so I assume that the test for >= 203
should be OK and cover both xterm and hterm.