Index: modules/system/system.api.php
===================================================================
RCS file: /cvs/drupal/drupal/modules/system/system.api.php,v
retrieving revision 1.102
diff -u -r1.102 system.api.php
--- modules/system/system.api.php	6 Nov 2009 03:59:06 -0000	1.102
+++ modules/system/system.api.php	14 Nov 2009 12:48:09 -0000
@@ -1973,7 +1973,10 @@
  *   to the user. If no message is returned, no message will be presented to the
  *   user.
  */
-function hook_update_N(&$sandbox = NULL) {
+function hook_update_N(&$sandbox) {
+  // For non-multipass updates, the signature can simply be;
+  // function hook_update_N() {
+
   // For most updates, the following is sufficient.
   db_add_field('mytable1', 'newcol', array('type' => 'int', 'not null' => TRUE, 'description' => 'My new integer column.'));