FD_RESOLVE_BENEATH
{ .f = FD_RESOLVE_BENEATH, .t = UF_RESOLVE_BENEATH },
{ .f = UF_RESOLVE_BENEATH, .t = FD_RESOLVE_BENEATH },
if ((fcntl(dfd, F_GETFD) & FD_RESOLVE_BENEATH) == 0)
if ((fcntl(dfd2, F_GETFD) & FD_RESOLVE_BENEATH) == 0)