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Killing a buffer makes its name unknown to Emacs and makes its text space available for other use.
The buffer object for the buffer that has been killed remains in
existence as long as anything refers to it, but it is specially marked
so that you cannot make it current or display it. Killed buffers retain
their identity, however; if you kill two distinct buffers, they remain
distinct according to eq
although both are dead.
If you kill a buffer that is current or displayed in a window, Emacs automatically selects or displays some other buffer instead. This means that killing a buffer can in general change the current buffer. Therefore, when you kill a buffer, you should also take the precautions associated with changing the current buffer (unless you happen to know that the buffer being killed isn't current). See Current Buffer.
If you kill a buffer that is the base buffer of one or more indirect buffers, the indirect buffers are automatically killed as well.
The buffer-name
of a killed buffer is nil
. You can use
this feature to test whether a buffer has been killed:
(defun buffer-killed-p (buffer) "Return t if BUFFER is killed." (not (buffer-name buffer)))
This function kills the buffer buffer-or-name, freeing all its memory for other uses or to be returned to the operating system. It returns
nil
.Any processes that have this buffer as the
process-buffer
are sent theSIGHUP
signal, which normally causes them to terminate. (The basic meaning ofSIGHUP
is that a dialup line has been disconnected.) See Deleting Processes.If the buffer is visiting a file and contains unsaved changes,
kill-buffer
asks the user to confirm before the buffer is killed. It does this even if not called interactively. To prevent the request for confirmation, clear the modified flag before callingkill-buffer
. See Buffer Modification.Killing a buffer that is already dead has no effect.
(kill-buffer "foo.unchanged") => nil (kill-buffer "foo.changed") ---------- Buffer: Minibuffer ---------- Buffer foo.changed modified; kill anyway? (yes or no) yes ---------- Buffer: Minibuffer ---------- => nil
After confirming unsaved changes,
kill-buffer
calls the functions in the listkill-buffer-query-functions
, in order of appearance, with no arguments. The buffer being killed is the current buffer when they are called. The idea of this feature is that these functions will ask for confirmation from the user. If any of them returnsnil
,kill-buffer
spares the buffer's life.
This is a normal hook run by
kill-buffer
after asking all the questions it is going to ask, just before actually killing the buffer. The buffer to be killed is current when the hook functions run. See Hooks.
This variable, if non-
nil
in a particular buffer, tellssave-buffers-kill-emacs
andsave-some-buffers
to offer to save that buffer, just as they offer to save file-visiting buffers. The variablebuffer-offer-save
automatically becomes buffer-local when set for any reason. See Buffer-Local Variables.