Answering myself on point 2. Man page of getgroups say we can get this maximum by using
sysconfig(_SC_NGROUPS_MAX) In my system this max is 65536. Perhaps it means that we have to use dynamic memory or a mix between static and dynamic. --- System information. --- Architecture: i386 Kernel: Linux 2.6.26-1-686 -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org