WordPress at a glance
filter is not described

attachment_url_to_postid filter-hook . WP 4.2.0

Filters an attachment id found by URL.


add_filter( 'attachment_url_to_postid', 'filter_function_name_7446', 10, 2 );
function filter_function_name_7446( $post_id, $url ){
	// filter...

	return $post_id;
The post_id (if any) found by the function.
The URL being looked up.

Where the hook is called

wp-includes/media.php 3943
return (int) apply_filters( 'attachment_url_to_postid', $post_id, $url );

Where the hook is used (in WP core)

Does not used.