WordPress at a glance
action is not described

pre_post_update action-hook . WP 2.5.0

Fires immediately before an existing post is updated in the database.

Usage

add_action( 'pre_post_update', 'action_function_name_2710', 10, 2 );
function action_function_name_2710( $post_ID, $data ){
	// action...
}
$post_ID(int)
Post ID.
$data(array)
Array of unslashed post data.

Where the hook is called

wp_insert_post()
wp-includes/post.php 3537
do_action( 'pre_post_update', $post_ID, $data );

Where the hook is used (in WP core)

Does not used.