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[2000-09-06 13:00 UTC] stas@php.net
[2000-10-31 17:55 UTC] mathieu@php.net
[2000-11-20 09:04 UTC] jmoore@php.net
[2003-04-29 05:00 UTC] mcp21 at cam dot ac dot uk
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Last updated: Sun Jun 28 06:00:01 2026 UTC |
Hi, Currently we are in great trouble with PHP4. We are heavily using references to objects in our current project and we need to create a reference from a class in the constructor of the class itself. But it is not working. I have tested it with PHP 4.0.1 and the new PHP 4.0.2. Finally I managed to write a short example script where it is not working. Here is the code that is refusing to work correctly: <?php class CParent { var $Ref; function setRef(&$Child) { $this->Ref=&$Child; } function drawRef() { printf(":%s:<br>\n",$this->Ref->Value); } } class CChild { var $Value; function CChild(&$Parent) { $Parent->setRef($this); } } $Parent=new CParent; $Child=new CChild($Parent); $Child->Value="Test"; $Parent->drawRef(); ?> This script creates a Parent-Class and a Child-Class. The constructor of the child class connects itself to the Parent class by passing its reference to the Parent. Then I change its property $Value to "Test" and call the Parents drawRef()-function. The drawRef-Function is printing the Value of the referenced object. Well, finally it is NOT printing the Value. The value seems to be empty. But the reference is working. If a add some methods to CChild, the Parent can call these methods through the reference. But all properties of CChild are empty. It looks like $Parent is working with a COPY of $Child and not with a reference. I thought there is something wrong with the setRef()-method, where I store the Reference in the $Ref-Variable, but... ....if I do the same in another way (Not using the constructor, instead writing the reference from Child to Parent manually) it is working. Here is the working code: <?php class CParent { var $Ref; function setRef(&$Child) { $this->Ref=&$Child; } function drawRef() { printf(":%s:<br>\n",$this->Ref->Value); } } class CChild { var $Value; // In this example I don't use the constructor to connect this // class to CParent } $Parent=new CParent; // Instead I call the setRef()-method manually to do it $Child=new CChild; $Parent->setRef($Child); $Child->Value="Test"; $Parent->drawRef(); ?> This script is working perfectly. So I wonder why is the first script not working? What is wrong about making a reference to $this in the constructor of $this? And to create just more confusion: If I assign a value to $this->Value in the constructor, this value is printed by drawRef() and values assigned later are ignored.