5 The ultimate goal of this branch is to implement support for opening
6 multiple, different tty devices and simultaneous X and tty frames from
7 a single Emacs session.
12 I'm Károly Lőrentey. My address: lorentey@elte.hu.
14 Patches or suggestions are welcome!
16 Retrieving the latest version of the branch:
18 tla register-archive lorentey@elte.hu--2004 http://lorentey.web.elte.hu/arch/2004/
19 tla get lorentey@elte.hu--2004/emacs--multi-tty--0 <directory>
27 Basic multi-tty support is there; there are some rough edges, but it
28 already seems to be usable. Emacsclient has been extended to support
29 opening a new terminal frame.
31 To try it out, start up the emacs server (M-x server-start), and then
32 (from a shell prompt on another terminal) start emacsclient with
36 You'll hopefully have two fully working frames on separate terminals.
37 If you exit emacs, both terminals should be restored to their previous
40 At the moment you can not close terminals without exiting Emacs --
41 this will soon be implemented.
43 X, Mac, Windows and DOS support is broken, probably doesn't even
44 compile -- this will be solved later.
46 Tested under GNU/Linux only.
53 ** Support for multiple terminal devices has been added. You can
54 specify a terminal device (`tty' parameter) and a terminal type
55 (`tty-type' parameter) to `make-terminal-frame'. `tty' must be a
56 terminal device created by the updated emacsclient, or there will
57 be problems with terminal input and window resizes. (The kernel
58 notifies processes about pending input or terminal resizes only on
59 the controlling terminal, so we need emacsclient to sit on the real
60 terminal device, create SIGIO signals upon terminal input, and
61 forward SIGWINCH signals to us.)
63 You can test for the presence of multiple terminal support by
64 testing for the `multi-tty' feature.
66 ** A make-frame-on-tty function has been added to make it easier to
67 create frames on new terminals.
69 ** Emacsclient has been extended to support opening a new terminal
81 (ex-TODO items with explanations.)
83 -- Introduce a new abstraction for terminal devices.
85 (Done, see struct tty_output. The abstraction is not yet
88 -- Change the bootstrap procedure to initialize tty_list.
90 (Done, but needs review.)
92 -- Change make-terminal-frame to support specifying another tty.
94 (Done, new frame parameters: `tty' and `tty-type'.)
96 -- Implement support for reading from multiple terminals.
98 (Done, read_avail_input tries to read from each terminal, until one
99 succeeds. MULTIKBOARD is not used. Secondary terminals don't send
102 -- other-frame should cycle through the frames on the `current'
105 (Done, by trivially modifiying next_frame and prev_frame.)
107 -- Support different terminal sizes.
111 -- Make sure terminal resizes are handled gracefully. (Could be
114 (Done. We don't get automatic SIGWINCH for additional ttys,
117 -- Extend emacsclient to automatically open a new tty when it connects
120 (Done. It's an ugly hack, needs more work.)
122 -- Redisplay must refresh the topmost frame on *all* terminals, not
123 just the initial terminal.
125 (Done, but introduced an ugly redisplay problems. Ugh.)
127 -- Fix redisplay problems.
129 (Done; it turned out that the entire Wcm structure must be moved
130 inside tty_output. Why didn't I catch this earlier?)
132 -- Provide a way for emacsclient to tell Emacs that the tty has been
135 (Done, simply forward the SIGWINCH signal.)
137 -- Each keypress should automatically select the frame corresponding
138 to the terminal that it was coming from. This means that Emacs
139 must know from which terminal the last keyboard event came from.
141 (Done, it was quite simple, the input event system already
142 supported multiple frames.)
144 -- Fix SIGIO issue with secondary terminals.
146 (Done, emacsclient signals Emacs after writing to the proxy pseudo
147 terminal. Note that this means that multi-tty does not work with
150 -- Make make-terminal-frame look up the `tty' and `tty-type' frame
151 parameters from the currently selected terminal before the global
156 -- Put all cached terminal escape sequences into struct tty_output.
157 Currently, they are still stored in global variables, so we don't
158 really support multiple terminal types.
160 (Done. It was not fun.)
162 -- Implement sane error handling after initialization. (Currently
163 emacs exits if you specify a bad terminal type.) The helpful error
164 messages must still be provided when Emacs starts.
168 -- Implement terminal deletion, i.e., deleting local frames, closing
169 the tty device and restoring its previous state without exiting
172 (Done, but at the moment only called when an error happens during
173 initialization. There is a memory corruption error around this
180 ** Fix mysterious memory corruption error with tty deletion. To
181 trigger it, try the following shell command:
183 while true; do TERM=no-such-terminal-definition emacsclient -h; done
185 Emacs usually dumps core after a few dozen iterations. (The bug
186 seems to be related to the xfree()ing or bzero()ing of
187 tty_output.Wcm or some other tty_output part. Maybe there are
188 outside references to struct Wcm? Why were these vars collected
189 into a struct before multi-tty support?)
191 The bug does not seem to happen if the error occurs before terminal
192 initialization or if I comment out all xfree()s in delete_frame.
193 Update: yes it does, although it is much rarer. Or maybe it's
196 ** C-g should work on secondary terminals.
198 ** Implement automatic deletion of terminals when the last frame on
199 that terminal is closed.
201 ** Make parts of struct tty_output accessible from Lisp. The device
202 name and the type is sufficient.
204 ** Export delete_tty to the Lisp environment, for emacsclient.
206 ** Implement support for starting an interactive Emacs session without
207 an initial frame. (The user would connect to it and open frames
208 later, with emacsclient.) Not necessarily a good idea.
210 ** Support raw secondary terminals. (This one is tricky, SIGIO works
211 only on the controlling terminal. The emacsclient solution works
212 nicely, so this is not that important anyway.)
214 ** What does interrupt_input do? I tried to disable it for raw
215 secondary tty support, but it does not seem to do anything useful.
217 ** Move optimalization parameters (costs) from union output_data to
218 a backend-neutral per-device structure.
220 ** Do tty output through term_hooks, too.
224 ** Allow simultaneous X and tty frames.
226 ** Fix Mac support (I can't do this myself).
228 ** Fix W32 support (I can't do this myself).
230 ** Fix DOS support (I can't do this myself).
234 ;;; arch-tag: 8da1619e-2e79-41a8-9ac9-a0485daad17d