尝试使用以下代码：

function themename_check_user_role( $role, $user_id = null ) {

    if ( is_numeric( $user_id ) )
    $user = get_userdata( $user_id );
    else
        $user = wp_get_current_user();

    if ( empty( $user ) )
    return false;

    return in_array( $role, (array) $user->roles );
}

// example use for the current user
if ( themename_check_user_role( \'customer\' )
    _e( "You\'ve got access!", \'themename\' );
else
    _e( "Sorry, you don\'t have access!", \'themename\' );