elisp: Special Events
20.9 Special Events
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Certain “special events” are handled at a very low level—as soon as they
are read. The ‘read-event’ function processes these events itself, and
never returns them. Instead, it keeps waiting for the first event that
is not special and returns that one.
Special events do not echo, they are never grouped into key
sequences, and they never appear in the value of ‘last-command-event’ or
‘(this-command-keys)’. They do not discard a numeric argument, they
cannot be unread with ‘unread-command-events’, they may not appear in a
keyboard macro, and they are not recorded in a keyboard macro while you
are defining one.
Special events do, however, appear in ‘last-input-event’ immediately
after they are read, and this is the way for the event’s definition to
find the actual event.
The events types ‘iconify-frame’, ‘make-frame-visible’,
‘delete-frame’, ‘drag-n-drop’, ‘language-change’, and user signals like
‘sigusr1’ are normally handled in this way. The keymap which defines
how to handle special events—and which events are special—is in the
variable ‘special-event-map’ (
Active Keymaps).
Info Catalog
elisp: Reading Input
elisp: Command Loop
elisp: Waiting