Retrieves meta field names for a post.

If there are no meta fields, then nothing (null) will be returned.

$post_id int Optional

Post ID. Default is the ID of the global $post.

array|void Array of the keys, if retrieved.

File: wp-includes/post.php. View all references

function get_post_custom_keys( $post_id = 0 ) {
	$custom = get_post_custom( $post_id );

	if ( ! is_array( $custom ) ) {
		return;
	}

	$keys = array_keys( $custom );
	if ( $keys ) {
		return $keys;
	}
}