A live frame is one that has not been deleted. When a frame is deleted, it is removed from its terminal display, although it may continue to exist as a Lisp object until there are no more references to it.
This function deletes the frame frame. The argument frame must specify a live frame (see below) and defaults to the selected frame.
It first deletes any child frame of frame (see Child Frames)
and any frame whose delete-before frame parameter (see Frame Interaction Parameters) specifies frame. All such deletions are
performed recursively; so this step makes sure that no other frames with
frame as their ancestor will exist. Then, unless frame
specifies a tooltip, this function runs the hook
delete-frame-functions (each function getting one argument,
frame) before actually killing the frame. After actually killing
the frame and removing the frame from the frame list, delete-frame
runs after-delete-frame-functions.
Note that a frame cannot be deleted as long as its minibuffer serves as
surrogate minibuffer for another frame (see Minibuffers and Frames).
Normally, you cannot delete a frame if all other frames are invisible,
but if force is non-nil, then you are allowed to do so.
This function returns non-nil if the frame frame has not
been deleted. The possible non-nil return values are like those
of framep. See Frames.
Some window managers provide a command to delete a window. These work
by sending a special message to the program that operates the window.
When Emacs gets one of these commands, it generates a
delete-frame event, whose normal definition is a command that
calls the function delete-frame. See Miscellaneous System Events.
This command deletes all frames on frame’s terminal, except
frame. If frame uses another frame’s minibuffer, that
minibuffer frame is left untouched. The argument frame must
specify a live frame and defaults to the selected frame. Internally,
this command works by calling delete-frame with force
nil for all frames that shall be deleted.
This function does not delete any of frame’s child frames (see Child Frames). If frame is a child frame, it deletes frame’s siblings only.
With the prefix argument iconify, the frames are iconified rather than deleted.