WordPress at a glance
action is not described

post_updated action-hook . WP 3.0.0

Fires once an existing post has been updated.

Usage

add_action( 'post_updated', 'action_function_name_6265', 10, 3 );
function action_function_name_6265( $post_ID, $post_after, $post_before ){
	// action...
}
$post_ID(int)
Post ID.
$post_after(WP_Post)
Post object following the update.
$post_before(WP_Post)
Post object before the update.

Where the hook is called

wp_insert_post()
wp-includes/post.php 3721
do_action( 'post_updated', $post_ID, $post_after, $post_before);

Where the hook is used (in WP core)

wp-includes/default-filters.php 339
add_action( 'post_updated', 'wp_save_post_revision', 10, 1 );
wp-includes/default-filters.php 376
add_action( 'post_updated', 'wp_check_for_changed_slugs', 12, 3 );
wp-includes/default-filters.php 380
add_action( 'post_updated', 'wp_check_for_changed_dates', 12, 3 );
wp-admin/includes/admin-filters.php 155
add_action( 'post_updated', array( 'WP_Privacy_Policy_Content', '_policy_page_updated' ) );