38.19 Window Systems

Emacs works with several window systems, most notably the X Window System. Both Emacs and X use the term "window", but use it differently. An Emacs frame is a single window as far as X is concerned; the individual Emacs windows are not known to X at all.

Variable: window-system

This variable tells Lisp programs what window system Emacs is running under. The possible values are

x

Emacs is displaying using X.

pc

Emacs is displaying using MS-DOS.

w32

Emacs is displaying using Windows.

mac

Emacs is displaying using a Macintosh.

nil

Emacs is using a character-based terminal.

Variable: window-setup-hook

This variable is a normal hook which Emacs runs after handling the initialization files. Emacs runs this hook after it has completed loading your init file, the default initialization file (if any), and the terminal-specific Lisp code, and running the hook term-setup-hook.

This hook is used for internal purposes: setting up communication with the window system, and creating the initial window. Users should not interfere with it.