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.
delete-frame&optional frame force
This function deletes the frame frame. Unless frame is a tooltip, it first runs the hook delete-frame-functions (each function gets one argument, frame). By default, frame is the selected frame.
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.
frame-live-p returns non-
nil if the frame
frame has not been deleted. The possible non-
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 Misc Events.