[TUHS] I swear! I rtfm'ed

From: clemc@ccc.com (Clem Cole)
Subject: [TUHS] I swear! I rtfm'ed
Date: Wed, 31 Dec 2014 15:14:00 -0500	[thread overview]
Message-ID: <CAC20D2MfLEhHhkfrH1E8QKo1__nALTWfFBtrhEXoX60NzC05TA@mail.gmail.com> (raw)
In-Reply-To: <CAHYQbfBF5ro-SCebomP0MOnC9ngSXmX59S6wsC=tZEcMdhzT_A@mail.gmail.com>

Jake - you have lots of help from others and using curses(3) is definitely
the right way to program.

But to answer your specific question about printf(string), according to
Chapter 3 (Programmer's Info) of my old VT-100 user's guide, I think what
is you are doing wrong is that "\033c" is not the ANSI clear to end of
screen command.

When I saw your message on my iPhone last night, the cache said - wait that
can't be correct.   But I could not remember why.   So I had to wait until
I got back home today to look in my basement.

As I suspected, it's not an ANSI sequence.  So are you running in VT-100
(ANSI) mode or VT52 mode?  I ask because it is close to the VT52 cursor
right command which is actually:  "\033C"  but I do not remember is case
mattered.

In VT52 mode you need to send the terminal:  "\033H\033J" to clear the
screen.

In ANSI mode, it becomes:  "\033[1;1\033[0J"

A few things to remember:
1.) Clear takes the current cursor position and clears from there to end of
X (where X depends on mode, and type of clear).  So you need to move the
cursor to home position (aka 1,1).

2.) VT-100's did not implement the full ANSI spec like Ann Arbor, Heathkit,
Wyse etc.  So there are a number of things that those terminals did
better.  A really good reason to you curses(3) because all the knowledge is
keep in the termcap and as a programmer you don't need to worry about it.

3.) I saw sites were VT52 mode was sometimes preferred because it was good
enough for most editing, and needed fewer chars to do manipulation.  On
slow serial lines, this sometimes was helpful.  That said, give me an AAA
any day.  Like others, I still miss that terminal. :-)

Clem

On Tue, Dec 30, 2014 at 5:56 PM, Jacob Ritorto <jacob.ritorto at gmail.com>
wrote:

> , but I can't see how you're supposed to clear the screen on a vt100 in
> 2.9BSD.  I guess printf'ing ("\033c") would do the trick, but I assumed
> there was a more proper way; something that leverages the vt100 termcap
> entry and does the right thing.  Anyone?
>
> thx
> jake
>
>
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