[OpenAFS] PAGs and group ids

[FB]

Hi,

a while ago I wrote a small utility which would tell, if it runs in a PAG or
not. The PAG was represented by 2 special gids back then. My utility doesn't
work anymore for some weeks now because PAGs seem to be represented
differently.

What is the "official" way of telling, if a process is in a PAG or not?
I would prefer some posix operation over a library function because
my utility is written in perl.

Thanks for any help,

Frank