Updating_frame vs. selected_frame in term.c.

[bpt/emacs.git] / README.multi-tty

			-*- coding: utf-8; -*-
GOAL
----

The ultimate goal of this branch is to implement support for opening
multiple, different tty devices and simultaneous X and tty frames from
a single Emacs session.

WHO IS DOING IT
---------------

I'm Károly Lőrentey.  My address: lorentey@elte.hu.

Patches or suggestions are welcome!


STATUS
------

We can create frames on new tty devices, but there are problems with
refresh (only the (single) selected frame is refreshed), and input is
read only from the initial terminal.  At the moment, the type of the
new terminals must be the same as the initial terminal.

To try it out, start up emacs, and evaluate the following:

	(make-terminal-frame '((tty . "/dev/pts/5") (tty-type . "xterm")))

(With your own values, of course.)  If you switch to the new frame
with M-x other-frame, the new tty is refreshed with the frame
contents.  The result of input from the original terminal appears on
the new.  If you exit emacs, both terminals are restored to their
previous states.

X, Mac, Windows and DOS support is broken.

NEWS
----

For the NEWS file:

** Support for multiple terminal devices has been added.  You can
   specify a terminal device (`tty' parameter) and a terminal type
   (`tty-type' parameter) to `make-terminal-frame'.


CHANGELOG
---------

See arch logs.


THINGS THAT ARE DONE
--------------------

-- Introduce a new abstraction for terminal devices.  

   (Done, see struct tty_output.  The abstraction is not yet
   complete.)


-- Change the bootstrap procedure to initialize tty_list.

   (Done, but needs review.)


-- Change make-terminal-frame to support specifying another tty.

   (Done, new frame parameters: `tty' and `tty-type'.)


THINGS TO DO
------------

** Make make-terminal-frame look up the tty and tty-type parameters
   from the currently selected terminal before the global default.

** Move optimalization parameters (costs) from union output_data to
   struct frame.

** Implement terminal deletion, i.e., closing the tty device and
   restoring its previous state without exiting Emacs.  This should be
   exported to the Lisp interpreter.

** Implement automatic deletion of terminals, when the last frame on
   that terminal is closed.

** Put all cached terminal escape sequences into struct tty_output.
   Currently, they are still stored in global variables, so we don't
   really support multiple terminal types.

** Support different terminal sizes.  (Should be solved by the
   previous entry.)

** Make sure terminal resizes are handled gracefully.  (Could be
   problematic.)

** Implement support for reading from multiple terminals.

** other-frame should cycle through the frames on the `current'
   terminal.  This means that Emacs must know from which terminal the
   last keyboard event came from.  (Multikeyboard support may help
   with this.)

** Redisplay must refresh the topmost on all terminals, not just
   the initial terminal.

** Make struct tty_output available from Lisp.

** Extend emacsclient to automatically open a new tty when it connects
   to Emacs.

** Implement support for starting an interactive Emacs session without
   an initial frame.  (The user would connect to it and open frames
   later, with emacsclient.)  Not necessary a good idea.

** Fix X support.

** Allow simultaneous X and tty frames.

** Fix Mac support (I can't do this myself).

** Fix W32 support (I can't do this myself).

** Fix DOS support (I can't do this myself).



;;; arch-tag: 8da1619e-2e79-41a8-9ac9-a0485daad17d