如何获取SimpleXMLElement对象到php中的数组

Question

如何在PHP中将SimpleXMLElement对象设置为数组，我的SimpleXMLElement对象响应代码为

Array
(
    [error_code] => SimpleXMLElement Object
        (
            [0] => 160040
        )

    [error_msg] => SimpleXMLElement Object
        (
            [0] => 验证码超出同模板同号码天发送上限
        )

    [smsMessageSid] => 
)