v1 = _vec_resize ((v1), _v(l2), \
(_v(l1) + _v(l2)) * sizeof ((v1)[0]), 0, align); \
memmove ((v1) + _v(l2), (v1), _v(l1) * sizeof ((v1)[0])); \
v1 = _vec_resize ((v1), _v(l2), \
(_v(l1) + _v(l2)) * sizeof ((v1)[0]), 0, align); \
memmove ((v1) + _v(l2), (v1), _v(l1) * sizeof ((v1)[0])); \