为什么我不能在php的try块中定义函数之前调用它 [英] Why can't i call a function before defining it in a try block in php

问题描述

当我在定义之前在try块内调用函数时.它给了我致命错误

When I call a function inside try block before defining. it gives me fatal error

我想做的是这个

try {
   echo someFunction();
   function someFunction()
   {
     return 'hello';
   }
 } catch (Exception $e ){
    return $e->getMessage();
 }

尽管我只是在try块上方修复了此粘贴功能，但我很好奇这里出了问题，应该行不通.它不在条件块中.

Although I just fix this just paste function above the try block I am curious what is wrong here should not it work. it is not inside in conditional block.

推荐答案

以条件方式定义函数时，必须先处理其定义，然后再调用它.只需像下面那样切换回声和功能即可.

When a function is defined in a conditional manner it's definition must be processed prior to being called. Just switch the echo and function like below.

try {
    function someFunction()
    {
        return 'hello';
    }
    echo someFunction();
} catch (Exception $e ){
    return $e->getMessage();
}

http://php.net/manual/en/functions.user -defined.php

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