get_post_custom_values()

get_post_custom_values() — Retrieves values for a custom post field. The parameters must not be considered optional. All of the post meta fields will be retrieved and only the meta field key values returned.

Inputs: $key (string): Optional. Meta field key. Default empty. $post_id (int): Optional. Post ID. Default is the ID of the global $post.

Returns string[]|null: Meta field values. Null if $key is not specified, if the post has no meta for that key, or if the post meta could not be retrieved. Values are always strings, as described for get_post_custom().