Cursor off/cursor on

[Brian K. White]

----- Original Message ----- 
From: "Barry Wiseman" <barry at gensoftdes.com>
To: "filePro list" <filepro-list at lists.celestial.com>
Sent: Tuesday, July 31, 2007 11:12 AM
Subject: Cursor off/cursor on


> These appear to require CF and CN entries in termcap.  I'm feeling really 
> dumb that I
> cannot discover the correct values for these entries.  Any help 
> appreciated.
> Terminal type is linux console.

There is no garantee that a given terminal even has that feature or any 
particular, or that it works right even if it claims to have it. It's 
entirely possible the linux console simply lacks this feature. Unlikely in 
this particular case, but just pointing out, different terminals supply 
different features, or impliment them differently from others etc.

Also, several termcap features are known by more than one name. Search docs 
for "cursor" not for CN.
And you may come across some other termcap field name that basically means 
cursor-on, and you just copy the escape sequence to CN where fp can see it.

Also, several outward appearing features can be accomplished more than one 
way, including sometimes very kludgy Rube Goldberg ways by using other 
features that do exist. A thing might be technically possible but only by a 
means so kludgy you should not do it. Like in this case, maybe the linux 
console has no dedicated feature for cursor-on-off, but maybe it's possible 
to, I dunno, move the cursor to a position off-screen or maybe somehow set 
it's color to match the underlying background color (and somehow track that 
as the cursor moves around to different colored areas of the screen), or 
maybe less kludgy but not immediately obvious, change it's size to 0 or -1 
lines.. or define a new scrolling window space off screen and shift focus 
there...


All that said:
Searching for "cursor" in "man console_codes" yields:
----snip----

ESC [ ? 25 h

DECTECM (default on): Make cursor visible.

----snip----


...not helpful since I see no cursor-off there nor a way to deduce "off" 
from "on" or other controls.


However, searching for "cursor" in "man termcap" yields:

---snip---
ve Normal cursor visible

vi Cursor invisible

---snip---


And searching for ":ve=" in the linux entry in /etc/termcap yields...

---snip---

:ve=\E[?25h\E[?0c:vi=\E[?25l\E[?1c:

---snip---



Voila.



Also, if /etc/termcap had not happened to define this feature, You could 
still search for the same feature in terminfo and translate the result to 
termcap. "man terminfo" to find the feature name, and then "infocmp |less" 
to see if that feature is defined in your current terminfo.



If that still hadn't yielded it, There are still more places to look. Next 
you would search both termcap and terminfo for the same feature in other 
similar terminals besides linux itself. The linux console is closest to 
vt220, which is almost the same as all the other vt's, vt100 is the most 
common and docs about it exist everywhere so you might find some odd feature 
documented there and it might turn out to work on linux even if the man page 
doesn't specifically mention it. It's also similar to xterm, and ALL of 
these are variants of "ansi".



Also, by search I mean searching google and not caring what OS the results 
are from. Terminals are used on all os's and there may be some amazingly 
detailed docs about ansi terminals in some sun or hpux docs or on a terminal 
manufacturer site itself.



Brian K. White    brian at aljex.com    http://www.myspace.com/KEYofR
+++++[>+++[>+++++>+++++++<<-]<-]>>+.>.+++++.+++++++.-.[>+<---]>++.
filePro  BBx    Linux  SCO  FreeBSD    #callahans  Satriani  Filk!