cap_getgrgid
struct group *cap_getgrgid(cap_channel_t *chan, gid_t gid);
grp = cap_getgrgid(capgrp, gids[i]);
grpc = cap_getgrgid(capgrp, GID_WHEEL);
grpc = cap_getgrgid(capgrp, GID_OPERATOR);
grp = cap_getgrgid(capgrp, GID_WHEEL);
grp = cap_getgrgid(capgrp, statp->st_gid);