Functions for displaying a buffer can be told to not use specific
windows by marking these windows as dedicated to their buffers.
display-buffer (see Choosing a Window for Displaying a Buffer) never uses a dedicated
window for displaying another buffer in it. get-lru-window and
get-largest-window (see Cyclic Ordering of Windows) do not
consider dedicated windows as candidates when their dedicated
argument is non-nil. The behavior of set-window-buffer
(see Buffers and Windows) with respect to dedicated windows is
slightly different, see below.
Functions supposed to remove a buffer from a window or a window from
a frame can behave specially when a window they operate on is dedicated.
We will distinguish four basic cases, namely where (1) the window is
not the only window on its frame, (2) the window is the only window on
its frame but there are other frames on the same terminal left, (3)
the window is the only window on the only frame on the same terminal,
and (4) the dedication’s value is side
(see Displaying Buffers in Side Windows).
In particular, delete-windows-on (see Deleting Windows)
handles case (2) by deleting the associated frame and cases (3) and (4)
by showing another buffer in that frame’s only window. The function
replace-buffer-in-windows (see Buffers and Windows) which is
called when a buffer gets killed, deletes the window in case (1) and
behaves like delete-windows-on otherwise.
When bury-buffer (see The Buffer List) operates on the
selected window (which shows the buffer that shall be buried), it
handles case (2) by calling frame-auto-hide-function
(see Quitting Windows) to deal with the selected frame. The other
two cases are handled as with replace-buffer-in-windows.
This function returns non-nil if window is dedicated to its
buffer and nil otherwise. More precisely, the return value is
the value assigned by the last call of set-window-dedicated-p for
window, or nil if that function was never called with
window as its argument. The default for window is the
selected window.
This function marks window as dedicated to its buffer if
flag is non-nil, and non-dedicated otherwise.
As a special case, if flag is t, window becomes
strongly dedicated to its buffer. set-window-buffer
signals an error when the window it acts upon is strongly dedicated to
its buffer and does not already display the buffer it is asked to
display. Other functions do not treat t differently from any
non-nil value.
You can also tell display-buffer to mark a window it creates as
dedicated to its buffer by providing a suitable dedicated
action alist entry (see Action Alists for Buffer Display).