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From: bc@cyb-eng.UUCP
Newsgroups: net.micro.pc
Subject: Re: READING PC/XT KEYPAD
Message-ID: <876@cyb-eng.UUCP>
Date: Tue, 3-Jun-86 11:03:07 EDT
Article-I.D.: cyb-eng.876
Posted: Tue Jun  3 11:03:07 1986
Date-Received: Fri, 6-Jun-86 19:41:16 EDT
References: <728@tekcbi.UUCP> <868@cyb-eng.UUCP> <5059@ut-sally.UUCP>
Distribution: na
Organization: Cyb Systems, Austin, TX
Lines: 31

> In article <868@cyb-eng.UUCP>, bc@cyb-eng.UUCP (Bill Crews) writes:
> > DOS calls stick to ASCII or "extended ASCII".  To get to all keys, you must
> > use BIOS and deal with the scan codes.  
> 
> Not so.  Read in a keyboard character using, say, "c = fgetc(stdin)" or
> whatever, then test for "c == NULL".  If it IS NULL, then bring in the
> character following, which tells you which "extended code" keystroke
> was done.  The IBM manual tells you the mapping between these "NULL-
> escaped" codes and the ASCII character set, but their chart is thoroughly
> confusing and I couldn't figure it out; I wrote a small program
> to print out this "second code" when a keypad or function key was
> pressed.  Works like a champ.  And, look ma!  No bios calls!
> -- 
> Ed Nather

You cannot get *all* keys with these codes, Ed.  For instance, the original
article asked about how to get at the 5 key when all modes are off, and
there is no such code for that key.

What you have just described is IBM's definition of "extended ASCII", which
is what I was referring to.  These codes are documented in the BASIC manual
(page D-7 in the 3.0 BASIC manual) and maybe somewhere else.  The only
confusing part to me relates to new or Brand X keyboards and how keys such
as keypad keys that have been separated from cursor keys return values.
But then I have the same confusion with respect to scan codes (BIOS) for
these keyboards.  Maybe if I were to buy a new Tech Ref . . . (or such a
keyboard).
-- 
	- bc -

..!{seismo,topaz,gatech,nbires,ihnp4}!ut-sally!cyb-eng!bc  (512) 835-2266