Re: Hi. How would I go about changing the keyboard .... -- LINUX5250



Jay... I think the main thing you're missing in your documentation here
is examples. :)

Also, tn5250 is currently referencing a file called
"/usr/local/share/tn5250/XTerm" rather than ~/.Xdefaults

Also, it appears that Paolo has the idea of "Ctrl-L" (holding down
control key and pressing L) with the idea of "Control_L" (the left
control key)



On Thu, 17 May 2001, Jay 'Eraserhead' Felice wrote:

> On Thu, May 17, 2001 at 10:20:19AM +0200, Paolo Fiore wrote:
> > > ----- Original Message -----
> > > From: Scott Klement <klemscot@xxxxxxxxxxxx>
> > > Sent: Tue, 27 Mar 2001 11:13:30 -0600 (CST
> > > Subject: Hi. How would I go about changing the keyboard ....
> > 
> > Scott, sorry if I've just partially quoted your original msg! I'm
> > dragging&dropping from IE to Outlook... and this is quite explaining what I
> > know about "gnu/linux"! Yep, I'm a newbie and know very very few about
> > shell, X, term, scripts.... but if you wanted a perfect Cobol program I'm
> > the one to ask for :)
> > 
> > So, good morning to the all mailing list!
> > 
> > > ~/tn5250/XTerm
> > > <Key>Control_L: string("\022") \n\
> > > causes Ctrl-R (interpreted as "Error Reset") when left control
> > > key is pressed.
> > > Personally, I run the program called "xev" and I type "man tn5250"
> > > to see what strings I want
> > 
> > I gave a look at the man page, but I didn't find those "hex" values...
> > - because I'd need another modification: having the Return acting as "New
> > Line"
> > Could also be I'm loosing something :( in yr example who's receiving Ctrl-R
> > & from who?
> > TN5250 feels the ctrl-L and sends to xterm a ctrl-R? And xterm knows through
> > the terminfo that ctrl-R means send to the AS an "Error reset", sounds?
> > Am I enough confused?
> 
> The terminfo actually knows nothing about Ctrl-R.  Ctrl-R is Ctrl-R.  The
> tn5250 program sends the AS/400 an error reset when it receives a Ctrl-R.
> 
> There are three layers involved (sometimes four).  I'm going to try to make
> a comprehensive, lucid explanation, with history, since this is not the first
> time this has come up:
> 
> First, there were dumb terminals - teletypes.  These sent ASCII codes from the
> keyboard to the the computer and displayed or printed ASCII codes sent from
> the computer.  You could use the CTRL key to send the lower control codes, 
>like
> you could send a newline with Ctrl+J or a form feed with Ctrl+L, etc.
> 
> But then the displays got more sophisiticated and needed escape sequences to
> control them to clear lines, move the cursor, set colors, etc.  The keyboards
> attached to them became more sophisticated and started sending escape 
>sequences
> back for functions keys like F1 and Home.  Unfortunately, no-one agreed on a
> standard for these codes - and different hardware had different quirks anyway
> (like on some you couldn't put a character in the lower right-hand corner
> without the screen scrolling).  /etc/termcap was invented as a database of
> escape sequences to do things like clear the screen and to interpret function
> keys.  termcap was replaced by terminfo, which is more comprehensive.  This
> is how an application can know that you've just pressed F1, which really sends
> something like <ESC> [ F 1 <NUL> (that's made up, but similar).  Most terminal
> "types" have only four F-keys (F1-F4) even though the terminals themselves
> nowadays usually have at least 10 and they can be shifted.
> 
> Okay.  So far, so good?   Now we have X windows and the xterminal.  This is
> different because xterm is _not_ a terminal, but a terminal "emulator".  In
> other words, it fakes sending escape sequences for function keys, and it can
> be told what to do when it receives a clear-screen escape sequence.  Xterm
> uses X windows' keyboard handling, which is much better (in some respects),
> since it has a unique number for each key, including function keys.
> 
> So we have to twiddle a bunch of things to get tn5250 to behave the way we
> would like it to.   Most xterm termcap/terminfo entries only have entries for
> 22 F-keys, for example, when we need 24.  We also don't have separate enter
> and newline keys.
> 
> So, we can use the xterm configuration (~/.Xdefaults) to tell the xterm what
> escape sequences to send when we press certain keys (When we press Shift+F12,
> send <ESC> [ F 2 4 <NUL>.  Then we can use termcap/terminfo definitions to
> tell the curses library (our application) what different escape sequences 
>mean.
> (When we receive <ESC> [ F 2 4 <NULL>, that means F24).  Then our applications
> interprets keys differently (When we get F24, send the screen with the Cmd24
> AID code, and when we receive Ctrl+R, clear the error indicator, etc.)
> 
> Hmm.  This didn't come out as clear as I had hoped.  If anyone wants to
> contribute commentary, I'll revise it.  If we can fix it up, I'll put it in
> the docs.
> 
> > 
> > Thank to you all
> > Paolo
> > P.S. Sorry my poor English
> > 
> 
> It's not bad at all.  You should see my French ;-)
> 
> -Jay 'Eraserhead' Felice
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