element_at
*value_le = element_at(c->info, c->ab, c->index);
fn(info->value_type.context, element_at(info, ab, 0), nr_entries);
memcpy(element_at(info, ab, i), value, vt->size);
vt->dec(vt->context, element_at(info, ab, new_nr - 1), delta);
r = fn(base + i, element_at(info, ab, i), context);
vt->inc(vt->context, element_at(info, ab, i), 1);
memcpy(value_le, element_at(info, ab, entry),
old_value = element_at(info, ab, entry);
element_at(wi->info, ab, i));