wp-includes/meta.php:1738Retrieves registered metadata for a specified object.
$object_typestring$object_idint$meta_keystringoptional''mixedfunction get_registered_metadata( $object_type, $object_id, $meta_key = '' ) { $object_subtype = get_object_subtype( $object_type, $object_id ); if ( ! empty( $meta_key ) ) { if ( ! empty( $object_subtype ) && ! registered_meta_key_exists( $object_type, $meta_key, $object_subtype ) ) { $object_subtype = ''; } if ( ! registered_meta_key_exists( $object_type, $meta_key, $object_subtype ) ) { return false; } $meta_keys = get_registered_meta_keys( $object_type, $object_subtype ); $meta_key_data = $meta_keys[ $meta_key ]; $data = get_metadata( $object_type, $object_id, $meta_key, $meta_key_data['single'] ); return $data; } $data = get_metadata( $object_type, $object_id ); if ( ! $data ) { return array(); } $meta_keys = get_registered_meta_keys( $object_type ); if ( ! empty( $object_subtype ) ) { $meta_keys = array_merge( $meta_keys, get_registered_meta_keys( $object_type, $object_subtype ) ); } return array_intersect_key( $data, $meta_keys );}Introduced in 4.6.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/meta.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.