PHP 中的 is_subclass_of ()函数

is_subclass_of () - 语法

is_subclass_of ( $object, $class_name );

它检查给定对象是否将class_name类作为其父对象之一。

is_subclass_of () - 返回值

如果对象属于class_name的子类，则此函数返回true，否则返回false。

is_subclass_of () - 示例

<?php
   //define a class
   class wid_fact {
      var $oink='moo';
   }
   
   //define a child class
   class wid_fact_child extends wid_fact {
      var $oink='oink';
   }
   
   //create a new object
   $WF=new wid_fact();
   $WFC=new wid_fact_child();
   
   if (is_subclass_of($WFC, 'wid_fact')) {
      echo "yes,\$WFC is a subclass of wid_fact\n";
   }else {
      echo "no,\$WFC is not a subclass of wid_fact\n";
   }
   
   if (is_subclass_of($WF, 'wid_fact')) {
      echo "yes,\$WF is a subclass of wid_fact\n";
   }else {
      echo "no,\$WF is not a subclass of wid_fact\n";
   }
?> 

它将产生以下输出-

yes, $WFC is a subclass of wid_fact
no, $WF is not a subclass of wid_fact