Function: window-system

window-system is a function defined in frame.c.

Signature

(window-system &optional FRAME)

Documentation

The name of the window system that FRAME is displaying through.

The value is a symbol:
 nil for a termcap frame (a character-only terminal),
 x for an Emacs frame that is really an X window,
 w32 for an Emacs frame that is a window on MS-Windows display,
 ns for an Emacs frame on a GNUstep or Macintosh Cocoa display,
 pc for a direct-write MS-DOS frame.

FRAME defaults to the currently selected frame.

Use of this function as a predicate is deprecated. Instead, use display-graphic-p or any of the other display-*-p predicates which report frame's specific UI-related capabilities.

Probably introduced at or before Emacs version 21.1.

Aliases

viper-device-type (obsolete since 27.1)

Source Code

// Defined in /usr/src/emacs/src/frame.c
{
  Lisp_Object type;
  if (NILP (frame))
    frame = selected_frame;

  type = Fframep (frame);

  if (NILP (type))
    wrong_type_argument (Qframep, frame);

  if (EQ (type, Qt))
    return Qnil;
  else
    return type;
}