php中关于register_shutdown_function函数的深入理解

register_shutdown_function(array(‘Debug','fatalError')); //定义PHP程序执行完成后执行的函数
set_error_handler(array(‘Debug','appError')); // 设置一个用户定义的错误处理函数
set_exception_handler(array(‘Debug','appException')); //自定义异常处理。

<?php
function test() {
  echo "test()";
}
register_shutdown_function("test");
echo "show: ";

//将输出
show:test()

<?php
 class ClassDemo {
     public function __construct() {
       register_shutdown_function(array($this, "f"));
     }
  
     public function f() {
       echo "f()";
     }
   }
 
   $demo = new ClassDemo();
   echo "before </br>";

//将输出
before
f()

<?php
function f($str) {
    echo $str."<br>";
}
 
register_shutdown_function("f","hello");

  class ClassDemo {
    public function __construct() {
      register_shutdown_function(array($this, "f"),"hello");
    }
 
    public function f($str) {
      echo "f():".$str;
    }
  }

$demo = new ClassDemo();
echo "before </br>";

//将输出
before
hello
f():hello