CURSES: magic cookie glitch characters

[Phong Vo[drew]]

In article <1990Nov15.061216.7165 at csusac.csus.edu>, jetfuel at csusac.csus.edu (Dave Jenks) writes:
> In article <felps.658590420 at convex.convex.com> felps at convex.com (Robert Felps) writes:
> >Can anyone shed some light on 'magic cookie glitch characters'?
> 
> A "magic cookie" is a byte location on a terminal screen which alters
> the "current attribute[s]".
> 
Actually, the right characterization is that a magic cookie is a mark on
the screen which alters the current attributes. There are two major families
of terminals, HP26xx and Televideo, that have this (mis)feature.
For the HPs, the marks have zero width (i.e., it does not take up one space on
the screen) while for the TVIs, the mark is 1-char width. These cookie critters
make life interesting for software like curses. The curses that I wrote, SysVr3.1 or
later, handles the HPs correctly and does the best it can for the TVIs.

	Phong Vo, att!ulysses!kpv