ar_next_avail
extern char **ar_next_avail __P((int list_handle));
if ((nfte = *(struct fstable **)ar_next_avail(fs_list))
ext_ptr = (struct cfextra **)ar_next_avail(xspace);
ext_ptr = (struct cfextra **)ar_next_avail(xspace);
ept_ptr = (struct cfent **)ar_next_avail(space);
class_ptr = (struct cl_attr **)ar_next_avail(cl_handle);