Using lgrp_root()

The lgrp_root() function returns the root lgroup ID.

#include <sys/lgrp_user.h>
lgrp_id_t lgrp_root(lgrp_cookie_t cookie);

The lgrp_root() function takes a cookie that represents a snapshot of the lgroup hierarchy and returns the root lgroup ID. For more information, see the lgrp_root(3LGRP) man page.