Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!snorkelwacker.mit.edu!ira.uka.de!smurf!artcom0!hb.maus.de!ms.maus.de!Kai_Henningsen
From: Kai_Henningsen@ms.maus.de (Kai Henningsen)
Newsgroups: comp.lang.pascal
Subject: Readkey alternative?
Message-ID: <14185@ms.maus.de>
Date: 27 Apr 91 12:05:00 GMT
Distribution: world,comp
Organization: Maus Mailbox Netz - UUCP-Gateway Bremen
Lines: 45


fer9483 @ tesla.njit.edu schrieb am 22.04.1991, 13:49

fe>I am writing a door for a friends BBS.. everything is fine except for one
fe>thing, the output doesn't work if i include the CRT unit..  this is
fe>not on my end, but on the BBS's and the way it handles output.. now this
fe>is all fine and dandy except for i need a function like readkey without
fe>using the crt unit.. just something that gets a key without waiting for
fe>a carriage return..

Well, I won't start explaining the old Crt-rewrite('')-problem, as that
wouldn't solve your problem; I'll only say that readkey works ONLY with the
keyboard.

There are several ways to work with the serial port instead; however, if you
want to use normal DOS redirection (which, from your description, I assume),
then the obvious solution seems to be using the DOS character I/O functions.

There are several; you might try each to determine which works best for you:

AH=01 -> AL=char        Character input with echo     ^C works
AH=06 DL=FF -> AL=char  Direct console I/O            ^C is normal char
AH=07 -> AL=char        Unfiltered character input without echo
                                                      ^C is normal char
AH=08 -> AL=char        Character input without echo  ^C works

You might also consider, for a replacement to keypress,
AH=0b -> AL=00/FF       Check input status            ^C works

For an example of how to use these:

uses DOS;
function ReadKeyDOS: char;
var r: registers;
begin
  r.ah:=$07;
  msdos(r);
  ReadKeyDOS:=chr(r.al);
end;

I'm not sure, but I believe ^C recognition can be disabled completely by
putting the input device into "raw" mode via an ioctl. If you need that, ask
again, and I'll look it up.

MfG Kai