New Features for Dealing with Buffers

• The new function buffer-modified-tick returns a buffer's modification-count that ticks every time the buffer is modified. It takes one optional argument, which is the buffer you want to examine. If the argument is nil (or omitted), the current buffer is used.
• buffer-disable-undo is a new name for the function formerly known as buffer-flush-undo. This turns off recording of undo information in the buffer given as argument.
• The new function generate-new-buffer-name chooses a name that would be unique for a new buffer--but does not create the buffer. Give it one argument, a starting name. It produces a name not in use for a buffer by appending a number inside of `<...>'.
• The function rename-buffer now takes an optional second argument which tells it that if the specified new name corresponds to an existing buffer, it should use generate-new-buffer-name to modify the name to be unique, rather than signaling an error. rename-buffer now returns the name to which the buffer was renamed.
• The function list-buffers now looks at the local variable list-buffers-directory in each non-file-visiting buffer, and shows its value where the file would normally go. Dired sets this variable in each Dired buffer, so the buffer list now shows which directory each Dired buffer is editing.
• The function other-buffer now takes an optional second argument visible-ok which, if non-nil, indicates that buffers currently being displayed in windows may be returned even if there are other buffers not visible. Normally, other-buffer returns a currently visible buffer only as a last resort, if there are no suitable nonvisible buffers.
• The hook kill-buffer-hook now runs whenever a buffer is killed.