> > i doubt if it makes thing faster, given the small NGROUPS.
> 
> Even if NGROUPS was 1600 it wouldn't make things faster. :)

then, what's the point to use binary search?

> > i don't think sorting groups is a good idea in general,
> > given that there's a filesystem which cares about the order of groups.
> > ie. nfs.
> 
> Why does NFS care about the order of groups?

because it can send only limited number of groups.

YAMAMOTO Takashi