How to know what codepoints are unassigned

[Patrik Fältström]

On 30 apr 2008, at 22.38, Mark Davis wrote:

> The code points that are unassigned (gc=Cn) but that should be
> DISALLOWED are all and only the Noncharacters.

What has confused me all the time here is that I interpreted what Mark  
say as if gc=Cn give the unassigned codepoints.

That is not true, wich shows that I misunderstood what he here wrote.

gc=Cn gives the unassigned codepoints PLUS the Noncharacter ones.

So, one can NOT use gc=Cn as a test for unassigned codepoints. It is  
more complicated than that.

     Patrik