Message-Id:	<m0vxvtO-000S1nC@natacha.inti.edu.ar>
Comments:	Authenticated sender is <salvador AT natacha DOT inti DOT edu DOT ar>
From:	"Salvador Eduardo Tropea (SET)" <salvador AT natacha DOT inti DOT edu DOT ar>
Organization:	INTI
To:	ovek AT arcticnet DOT no (Ove Kaaven), djgpp AT delorie DOT com
Date:	Fri, 21 Feb 1997 17:36:24 +0000
MIME-Version:	1.0
Subject:	Re: Allegro: missing KEYs?

Hi:

> ao950 AT FreeNet DOT Carleton DOT CA (Paul Derbyshire) wrote:
> 
> >I noticed also, it can distinguish left and right shift but not left and
> >right control or left and right alt. Is this normal? I know that keyboards
> >have different scan codes for left and right alt since I've seen other
> >programs that distinguish left and right alt. I don't particularly need to
> >distinguish them though.
> 
> No they don't really have different scan codes for left and right alt
> for standard PC keyboard setups, due to XT (was that 83 keys?)
> keyboard compatibility. The way modern 101/102-key keyboards
> distinguish them is by a prefix byte (0xE0). So you have:
> Left Alt: 0x38
> Right Alt: 0xE0 0x38
> Left Ctrl: 0x1D
> Right Ctrl: 0xE0 0x1D
> 
> With simple keyboard handlers that only set a table according to scan
> code, and ignoring prefix bytes, you can't distinguish left and right
> Alt/Ctrl. (Linux solves this by adding pseudo-scancodes, e.g. converts
> 0xE0 0x38 to 0x64, 0xE0 0x1D to 0x61, etc, for its raw keyboard mode.)

But that can be very easily made in Allegro. Allegro just don't do that because 
it can break all Allegro applications.

SET 
--------------- 0 --------------------------------
Salvador Eduardo Tropea (SET).
Address: Curapaligue 2124, Caseros, 3 de Febrero
Buenos Aires, (1678), ARGENTINA
TE: +(541) 759 0013

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