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28.16 Quitting Windows

When you want to get rid of a window used for displaying a buffer, you can call delete-window or delete-windows-on (see Deleting Windows) to remove that window from its frame. If the buffer is shown on a separate frame, you might want to call delete-frame (see Deleting Frames) instead. If, on the other hand, a window has been reused for displaying the buffer, you might prefer showing the buffer previously shown in that window, by calling the function switch-to-prev-buffer (see Window History). Finally, you might want to either bury (see Buffer List) or kill (see Killing Buffers) the window's buffer.

The following command uses information on how the window for displaying the buffer was obtained in the first place, thus attempting to automate the above decisions for you.

— Command: quit-window &optional kill window

This command quits window and buries its buffer. The argument window must be a live window and defaults to the selected one. With prefix argument kill non-nil, it kills the buffer instead of burying it. It calls the function quit-restore-window described next to deal with the window and its buffer.

— Function: quit-restore-window &optional window bury-or-kill

This function handles window and its buffer after quitting. The optional argument window must be a live window and defaults to the selected one. The function's behavior is determined by the four elements of the list specified by window's quit-restore parameter (see Window Parameters).

The first element of the quit-restore parameter is one of the symbols window, meaning that the window has been specially created by display-buffer; frame, a separate frame has been created; same, the window has only ever displayed this buffer; or other, the window showed another buffer before. frame and window affect how the window is quit, while same and other affect the redisplay of buffers previously shown in window.

The parameter's second element is either one of the symbols window or frame, or a list whose elements are the buffer shown in window before, that buffer's window start and window point positions, and window's height at that time. If that buffer is still live when window is quit, then this function may reuse window to display it.

The third element is the window selected at the time the parameter was created. If this function deletes window, it subsequently tries to reselect the window named by that element.

The fourth element is the buffer whose display caused the creation of this parameter. This function may delete window if and only if it still shows that buffer.

This function will try to delete window if and only if (1) the first element of its quit-restore parameter is either window or frame, (2) the window has no history of previously-displayed buffers and (3) the fourth element of the quit-restore parameter specifies the buffer currently displayed in window. If window is part of an atomic window (see Atomic Windows), it will try to delete the root of that atomic window instead. In either case, it tries to avoid signaling an error when window cannot be deleted.

If window shall be deleted, is the only window on its frame and there are other frames on that frame's terminal, the value of the optional argument bury-or-kill determines how to proceed with the window. If bury-or-kill equals kill, the frame is deleted unconditionally. Otherwise, the fate of the frame is determined by calling frame-auto-hide-function (see below) with that frame as sole argument.

If the third element of the quit-restore parameter is a list of buffer, window start (see Window Start and End), and point (see Window Point), and that buffer is still live, the buffer will be displayed, and start and point set accordingly. If, in addition, window's buffer was temporarily resized, this function will also try to restore the original height of window.

Otherwise, if window was previously used for displaying other buffers (see Window History), the most recent buffer in that history will be displayed. In either case, if window is not deleted, its quit-restore parameter is reset to nil.

The optional argument bury-or-kill specifies how to deal with window's buffer. The following values are handled:

nil
This means to not deal with the buffer in any particular way. As a consequence, if window is not deleted, invoking switch-to-prev-buffer will usually show the buffer again.
append
This means that if window is not deleted, its buffer is moved to the end of window's list of previous buffers, so it's less likely that a future invocation of switch-to-prev-buffer will switch to it. Also, it moves the buffer to the end of the frame's buffer list.
bury
This means that if window is not deleted, its buffer is removed from window's list of previous buffers. Also, it moves the buffer to the end of the frame's buffer list. This value provides the most reliable remedy to not have switch-to-prev-buffer switch to this buffer again without killing the buffer.
kill
This means to kill window's buffer.

Typically, the display routines run by display-buffer will set the quit-restore window parameter correctly. It's also possible to set it manually, using the following code for displaying buffer in window: 

          (display-buffer-record-window type window buffer)
          
          (set-window-buffer window buffer)
          
          (set-window-prev-buffers window nil)

Setting the window history to nil ensures that a future call to quit-window can delete the window altogether.

The following option specifies how to deal with a frame containing just one window that should be either quit, or whose buffer should be buried.

— User Option: frame-auto-hide-function

The function specified by this option is called to automatically hide frames. This function is called with one argument—a frame.

The function specified here is called by bury-buffer (see Buffer List) when the selected window is dedicated and shows the buffer to bury. It is also called by quit-restore-window (see above) when the frame of the window to quit has been specially created for displaying that window's buffer and the buffer is not killed.

The default is to call iconify-frame (see Visibility of Frames). Alternatively, you may specify either delete-frame (see Deleting Frames) to remove the frame from its display, make-frame-invisible to make the frame invisible, ignore to leave the frame unchanged, or any other function that can take a frame as its sole argument.

Note that the function specified by this option is called only if the specified frame contains just one live window and there is at least one other frame on the same terminal.

For a particular frame, the value specified here may be overridden by that frame's auto-hide-function frame parameter (see Frame Interaction Parameters).