The committee has gone around several times on the
stack effects. Whatever is decided will violate somebody's
practice and penalize some machine. This way doesn't interfere
with type-ahead on some systems, while requiring the
implementation of a single-character buffer on machines where
polling the keyboard inevitably results in the destruction of
Use of KEY
indicates that the
application does not wish to process non-character events,
so they are discarded, in anticipation of eventually receiving
a valid character. Applications wishing to handle non-character
events must use EKEY
. It is possible
to mix uses of KEY?
within a single application, but
the application must use KEY?
when it wishes to discard non-character events until a valid
character is received.