[pdftex] char protruding

[Han The Thanh]

> I've got a new "problem" concerning the char protruding feature.
> I'm using SIunits.sty and there is at one point an 180° at the end
> of the line. And I think the degree should poke into the margin.
> 
> But I don't know how to get this -- even worse: is it possible to
> make an automated protruding for such a construct? The degree of
> SIunits is defined as follows:
>         \ensuremath{^{\circ}}

probably the easiest way is to append a `null' character after such
constructions. Such a character should have zero width/height/depth, but
non-zero character protruding factor (best available in some virtual font).
I has similar applications of character protruding. 

Thanh