note 52962 added to language.oop.constructor

This will save you time if you're building a class hierarchy with 2 or more levels of inheritance. $this always refers to the CURRENT INSTANCE. Therefore if you have: class A{ function A(){ } // .... } class B extends A{ function B(){ // keep these 2 lines in mind $parentClass = get_parent_class($this); $this->$parentClass(); } // .... } class C extends B{ function C(){ $parentClass = get_parent_class($this); $this->$parentClass(); // here you will get into an infinite loop calling B(); } // .... } Explanation: $this is an instance variable referring to the CURRENT INSTANCE, therefore the $this variable on class B will always be an instance of C, therefore get_parent_class($this) in class B will call the constructor of C's parent class, which is B again. This is a hard to track error if you're a novice on PHP's OO features mainly because PHP will not produce any warnings, errors or notices, nor will it log anything to Apache or the error_log file. Keywords : infinite recursion, parent constructor, subclass ---- Manual Page -- http://www.php.net/manual/en/language.oop.constructor.php Edit -- http://master.php.net/manage/user-notes.php?action=edit+52962 Delete: added to the manual -- http://master.php.net/manage/user-notes.php?action=delete+52962&report=yes&reason=added+to+the+manual Delete: bad code -- http://master.php.net/manage/user-notes.php?action=delete+52962&report=yes&reason=bad+code Delete: spam -- http://master.php.net/manage/user-notes.php?action=delete+52962&report=yes&reason=spam Delete: useless -- http://master.php.net/manage/user-notes.php?action=delete+52962&report=yes&reason=useless Delete: other reasons -- http://master.php.net/manage/user-notes.php?action=delete+52962&report=yes Reject -- http://master.php.net/manage/user-notes.php?action=reject+52962&report=yes Search -- http://master.php.net/manage/user-notes.php