WordPress at a glance
function is not described

get_registered_meta_keys() WP 4.6.0

Retrieves a list of registered meta keys for an object type.

  • Since 4.9.8 The $object_subtype parameter was added.

No Hooks.

Return

Array. List of registered meta keys.

Usage

get_registered_meta_keys( $object_type, $object_subtype );
$object_type(string) (required)
The type of object. Post, comment, user, term.
$object_subtype(string)
The subtype of the object type.
Default: ''

Code of get registered meta keys: wp-includes/meta.php WP 5.2.1

<?php
function get_registered_meta_keys( $object_type, $object_subtype = '' ) {
	global $wp_meta_keys;

	if ( ! is_array( $wp_meta_keys ) || ! isset( $wp_meta_keys[ $object_type ] ) || ! isset( $wp_meta_keys[ $object_type ][ $object_subtype ] ) ) {
		return array();
	}

	return $wp_meta_keys[ $object_type ][ $object_subtype ];
}