Emacs mode for gdb

[Nick Roberts <nick@nick.uklinux.net>]

I have written a mode for Emacs that allows it to act as a GUI for GDB
(gdb-ui.el) that has recently gone into the Emacs repository
(http://savannah.gnu.org/projects/emacs). It is based on an earlier file
called gdba.el that was once part of the GDB distribution. I understand that
this file was written mainly by Jim Kingdon but in it there is a comment about
the queuing used:


;; Note: Stuff enqueued here will be sent to the next prompt, even if it
;; is a query, or other non-top-level prompt.  To guarantee stuff will get
;; sent to the top-level prompt, currently it must be put in the idle queue.
;;				 ^^^^^^^^^
;; [This should encourage gdb extensions that invoke gdb commands to let
;;  the user go first; it is not a bug.     -t]
;;

Does anyone know what these 'gdb extensions' are or why two queues (high and
low priority) are needed ? Or who 't' is ?

Nick Roberts