Objects and references

One of the key-points of PHP OOP that is often mentioned is that "objects are passed by references by default". This is not completely true. This section rectifies that general thought using some examples.

A PHP reference is an alias, which allows two different variables to write to the same value. In PHP, an object variable doesn't contain the object itself as value. It only contains an object identifier which allows object accessors to find the actual object. When an object is sent by argument, returned or assigned to another variable, the different variables are not aliases: they hold a copy of the identifier, which points to the same object.

Example #1 References and Objects

<?php
class {
    public 
$foo 1;
}  

$a = new A;
$b $a;     // $a and $b are copies of the same identifier
             // ($a) = ($b) = <id>
$b->foo 2;
echo 
$a->foo."\n";


$c = new A;
$d = &$c;    // $c and $d are references
             // ($c,$d) = <id>

$d->foo 2;
echo 
$c->foo."\n";


$e = new A;

function 
foo($obj) {
    
// ($obj) = ($e) = <id>
    
$obj->foo 2;
}

foo($e);
echo 
$e->foo."\n";

?>

The above example will output:

2
2
2

Here you can write a comment


Please enter at least 10 characters.
Loading... Please wait.
* Pflichtangabe
There are no comments available yet.

Was genau bedeutet "Vibe Coding"? Ein tiefgehender Blick für Entwickler

In der Welt der Softwareentwicklung gibt es unzählige Wege, wie man an ein Projekt herangeht. Manche schwören auf strikte Planung, andere auf bewährte Algorithmen und wieder andere lassen sich von etwas ganz anderem leiten: ihrem Gefühl. ...

admin

Autor : admin
Category: Software & Web-Development

PHP cURL Tutorial: Using cURL to Make HTTP Requests

cURL is a powerful PHP extension that allows you to communicate with different servers using various protocols, including HTTP, HTTPS, FTP, and more. ...

TheMax

Autor : TheMax
Category: PHP-Tutorials

Midjourney Tutorial - Instructions for beginners

There is an informative video about Midjourney, the tool for creating digital images using artificial intelligence, entitled "Midjourney tutorial in German - instructions for beginners" ...

Mike94

Autor : Mike94
Category: KI Tutorials

Publish a tutorial

Share your knowledge with other developers worldwide

Share your knowledge with other developers worldwide

You are a professional in your field and want to share your knowledge, then sign up now and share it with our PHP community

learn more

Publish a tutorial