api.php

<?php

function array_orderby() {
    $args = func_get_args();
    $data = array_shift( $args );

    if ( ! is_array( $data ) ) {
        return array();
    }

    $multisort_params = array();
    foreach ( $args as $n => $field ) {
        if ( is_string( $field ) ) {
            $tmp = array();
            foreach ( $data as $row ) {
                $tmp[] = $row[ $field ];
            }
            $args[ $n ] = $tmp;
        }
        $multisort_params[] = &$args[ $n ];
    }

    $multisort_params[] = &$data;
    call_user_func_array( 'array_multisort', $multisort_params );
    return end( $multisort_params );
}