[GRASS5] [bug #998] (grass) Vask (curses) problems with KDE terminal

Glynn Clements glynn.clements at virgin.net
Wed Apr 3 16:02:15 EST 2002


Markus Neteler wrote:

> > > Subject: Vask (curses) problems with KDE terminal
> > 
> > > a long term problem on KDE is that in KDE terminal the carriage return (or whatever)
> > > doesn't seem to work properly. The problem must be related to curses in the
> > > VASK library.
> > 
> > This sounds like a curses problem; in which case, GRASS can't do
> > anything about it.
> 
> ... if so: why does it work well for xterm? Or does curses behave
> differently in xterm and KDE (or other) terminals? 

Yes and no.

In general[1], curses uses the value of $TERM to obtain a terminal
description from either termcap or terminfo[2]. It uses that
description to determine exactly which codes should be sent to the
terminal to redraw the screen.

If curses doesn't redraw the screen correctly, this indicates that the
terminfo (or termcap) entry corresponding to $TERM doesn't accurately
describe the behaviour of the terminal.

Note that terminal emulators (e.g. xterm) have historically been
problematic. Their behaviour is often highly configurable, but any
given terminal description corresponds to a specific configuration.

The usual way to support this is to provide multiple terminal
descriptions (look in e.g. /usr/share/terminfo/x for all of the
different xterm variants), corresponding to different option settings. 
However, this only works if the user ensures that TERM is set to the
variant which matches the settings which are actually in use.

[1] Some systems allow a complete terminal description to be specified
via $TERMCAP.

[2] Depending upon how curses was compiled. Some older systems only
support termcap. Newer systems may either only use terminfo, or try
terminfo first, then try termcap if a terminfo entry can't be found.

-- 
Glynn Clements <glynn.clements at virgin.net>



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