error function

[Shai Ayal]

Hi all,

In the process of adding new graphics property types (sorry it's
taking soooo long), I came upon the error function. Can someone
explain it to me?
does it throw an exception?
what does it do except setting the error_state flag?
when will the error message be printed?
Is it the "recommended" way to handle errors of the sort of
incompatible assignments -- i.e. trying to assing a number to a string
type?

Thanks,
Shai