Re: Keyboard filter (to work with a Card Reader)

From: Ray Trent (ratrent_at_nospam.nospam)
Date: 11/16/04 

Date: Tue, 16 Nov 2004 14:09:59 -0800

It's not real clear what you are trying to accomplish, but I'll try to
answer your questions:

Maria Penedo wrote:
> - is a driver the best solution for this case?

It really depends on what you're trying to do. If all you want to do is
look at the keyboard data coming in and respond when a particular
sequence arrives (without changing the stream of keys sent to
applications/the OS) then you don't really need a driver. A simple
user-mode keyboard hook would be much easier.

If you need to alter the stream of characters sent to the OS/apps, then
a kbfiltr-like driver is the only way to do that.

> - If yes, how can I create a buffer in the kbfiltr sample to keep reading
> chars when some kind of input is read?

Again, it's not completely clear what you're trying to do. You could
create such a buffer easily enough (trap the callback and don't send
things on unless/until you want to).

However, you have to be very careful about how you do something like
this. You need to make sure the card reader sends some kind of
out-of-band signal (such as invalid scancodes) to trigger your
buffering, because otherwise you're going to find it hard to avoid
interfering with normal use of the keyboard. You can't really refuse to
send a "%" key up to the OS just because it might eventually be followed
by "a670812". 

-- 
../ray\..

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