dongyi7669 2017-09-26 07:17
浏览 28


I'm making a program that will only accept a boolean value as parameter. I thought I could instanceof to do this, but it does not work as I expected.

function test (boolean $param) {
    echo $param;

When I use it in my program, I get following error message:

Argument 1 passed to test() must be an instance of boolean

Is instanceof the right method to do this and how does it work?

  • 写回答

2条回答 默认 最新

  • duanjing7298 2017-09-26 07:42

    As per the manual on type-declarations, it's stated that you need to use bool instead of boolean when type-declaring for a boolean value. This also requires PHP-version 7.0.0 or higher.

    function test (bool $param) {}

    If you are on a PHP version lower than 7.0.0, you cannot use the boolean type-declaration at all. However, you can check if a boolean argument was supplied by using is_bool($param), then return false, null or throw an exception instead, and deal with it that way. You can also issue a user-warning (by trigger_error()) if you think its appropriate.

    本回答被题主选为最佳回答 , 对您是否有帮助呢?



  • ¥15 有人能看一下我宿舍管理系统的报修功能该怎么改啊?链表那里总是越界
  • ¥15 cs loadimage运行不了,easyx也下了,没有用
  • ¥15 r包runway详细安装教程
  • ¥15 Html中读取Json文件中数据并制作表格
  • ¥15 谁有RH342练习环境
  • ¥15 STM32F407 DMA中断问题
  • ¥15 uniapp连接阿里云无法发布消息和订阅
  • ¥25 麦当劳点餐系统代码纠错
  • ¥15 轮班监督委员会问题。
  • ¥20 关于变压器的具体案例分析