为什么set_exception_handler（func）不能捕获异常？

Question

一个例外是在我关机功能抛出不抓到一个try/catch块内，例如：

<?php 

set_exception_handler(function($e){ 
    echo "exception handled"; // not echoed 
}); 

register_shutdown_function(function(){ 
    throw new Exception("test"); // this should be caught by the exception handler above, but it doesn't 
}); 

Live run.

运行上面的代码给出：

Fatal error: Uncaught exception 'Exception' with message 'test'

然而PHP Manual声称：

set_exception_handler sets the default exception handler if an exception is not caught within a try/catch block. Execution will stop after the exception_handler is called.

为什么exception_handler没有捕获异常抛出？

Answer 1

因为它超出范围...

http://www.php.net/manual/en/function.register-shutdown-function.php

Registers a callback to be executed after script execution finishes or exit() is called.

那一定是你处理剥离下来作为脚本的执行已经完成，并在事实上关闭。