These variables control details of how the echo area works.
This variable controls where the cursor appears when a message is
displayed in the echo area. If it is non-nil, then the cursor
appears at the end of the message. Otherwise, the cursor appears at
point—not in the echo area at all.
The value is normally nil; Lisp programs bind it to t
for brief periods of time.
This normal hook is run whenever the echo area is cleared—either by
(message nil) or for any other reason.
This variable determines how much time should elapse before command characters echo. Its value must be a number, and specifies the number of seconds to wait before echoing. If the user types a prefix key (such as C-x) and then delays this many seconds before continuing, the prefix key is echoed in the echo area. (Once echoing begins in a key sequence, all subsequent characters in the same key sequence are echoed immediately.)
If the value is zero, then command input is not echoed.
Normally, displaying a long message resizes the echo area to display
the entire message, wrapping long line as needed. But if the variable
message-truncate-lines is non-nil, long lines of
echo-area message are instead truncated to fit the mini-window width.
The variable max-mini-window-height, which specifies the
maximum height for resizing minibuffer windows, also applies to the
echo area (which is really a special use of the minibuffer window;
see Minibuffer Windows).