Emacs represents each terminal, whether graphical or text-only, as a terminal object data type (see Terminal Type). On GNU and Unix systems, Emacs can use multiple terminals simultaneously in each session. On other systems, it can only use a single terminal. Each terminal object has the following attributes:
terminal-live-p (i.e., x,
t, w32, ns, or pc). See Frames.
There is no primitive for creating terminal objects. Emacs creates
them as needed, such as when you call make-frame-on-display
(which is described below).
This function returns the file name of the device used by terminal. If terminal is omitted or
nil, it defaults to the selected frame's terminal. terminal can also be a frame, meaning that frame's terminal.
This function returns a terminal whose device name is given by device. If device is a string, it can be either the file name of a terminal device, or the name of an X display of the form ‘host:server.screen’. If device is a frame, this function returns that frame's terminal;
nilmeans the selected frame. Finally, if device is a terminal object that represents a live terminal, that terminal is returned. The function signals an error if its argument is none of the above.
This function deletes all frames on terminal and frees the resources used by it. It runs the abnormal hook
delete-terminal-functions, passing terminal as the argument to each function.If terminal is omitted or
nil, it defaults to the selected frame's terminal. terminal can also be a frame, meaning that frame's terminal.Normally, this function signals an error if you attempt to delete the sole active terminal, but if force is non-
nil, you are allowed to do so. Emacs automatically calls this function when the last frame on a terminal is deleted (see Deleting Frames).
An abnormal hook run by
delete-terminal. Each function receives one argument, the terminal argument passed todelete-terminal. Due to technical details, the functions may be called either just before the terminal is deleted, or just afterwards.
A few Lisp variables are terminal-local; that is, they have a
separate binding for each terminal. The binding in effect at any time
is the one for the terminal that the currently selected frame belongs
to. These variables include default-minibuffer-frame,
defining-kbd-macro, last-kbd-macro, and
system-key-alist. They are always terminal-local, and can
never be buffer-local (see Buffer-Local Variables).
On GNU and Unix systems, each X display is a separate graphical
terminal. When Emacs is started from within the X window system, it
uses the X display chosen with the DISPLAY environment
variable, or with the ‘--display’ option. See Initial Options. Emacs can connect to other X
displays via the command make-frame-on-display. Each X display
has its own selected frame and its own minibuffer windows; however,
only one of those frames is “the selected frame” at any given
moment (see Input Focus). Emacs can even connect to other
text-only terminals, by interacting with the emacsclient
program. See Emacs Server.
A single X server can handle more than one display. Each X display has a three-part name, ‘host:server.screen’. The first two parts, host and server, identify the X server; the third part, screen, identifies a screen number on that X server. When you use two or more screens belonging to one server, Emacs knows by the similarity in their names that they share a single keyboard.
On some “multi-monitor” setups, a single X display outputs to more than one monitor. Currently, there is no way for Emacs to distinguish between the different physical monitors.
This function creates and returns a new frame on display, taking the other frame parameters from the alist parameters. display should be the name of an X display (a string).
Before creating the frame, this function ensures that Emacs is “set up” to display graphics. For instance, if Emacs has not processed X resources (⁖, if it was started on a text-only terminal), it does so at this time. In all other respects, this function behaves like
make-frame(see Creating Frames).
This function returns a list that indicates which X displays Emacs has a connection to. The elements of the list are strings, and each one is a display name.
This function opens a connection to the X display display, without creating a frame on that display. Normally, Emacs Lisp programs need not call this function, as
make-frame-on-displaycalls it automatically. The only reason for calling it is to check whether communication can be established with a given X display.The optional argument xrm-string, if not
nil, is a string of resource names and values, in the same format used in the .Xresources file. See X Resources. These values apply to all Emacs frames created on this display, overriding the resource values recorded in the X server. Here's an example of what this string might look like:"*BorderWidth: 3\n*InternalBorder: 2\n"If must-succeed is non-
nil, failure to open the connection terminates Emacs. Otherwise, it is an ordinary Lisp error.
This function closes the connection to display display. Before you can do this, you must first delete all the frames that were open on that display (see Deleting Frames).