PHP - Class/Object class_alias() Function

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The PHP Class/Object class_alias() function is used to create an alias name for the class. This means that you can rename a class and refer to it by either its original name or alias name. And most importantly aliased class has similar functionality like the original class.

Syntax

Below is the syntax of the PHP Class/Object class_alias() function −

bool class_alias (
   string $class, 
   string $alias, 
   bool $autoload = true
)

Parameters

Below are the parameters of the class_alias() function −

• $class − It is the property that holds the original class name.

• $alias − It is the alias name to give to the original class.

• $autoload − Whether to autoload the class if it is not already loaded. Its default value is true.

Return Value

The class_alias() function returns TRUE on success and FALSE on failure.

PHP Version

First introduced in core PHP 5.3.0, the class_alias() function continues to function easily in PHP 7, and PHP 8.

Example 1

Here is the basic example of the PHP Class/Object class_alias() function to create an alias for a class and use it to initialize an object.

<?php
   // Define the original class here
   class MyClass {
      public function hello() {
          return "Hello from MyClass!";
      }
   }
  
   class_alias('MyClass', 'AliasClass');
  
   $obj = new AliasClass();
   echo $obj->hello();
?>

Output

Here is the outcome of the following code −

Hello from MyClass!

Example 2

In the below PHP code we will use the class_alias() function and alias a class which belongs to a namespace.

<?php
   // Define namespace here
   namespace MyNamespace;

   // Define a class here
   class MyClass {
       public function hello() {
           return "Hello from MyNamespace\\MyClass!";
       }
   }
   
   class_alias('MyNamespace\\MyClass', 'AliasClass');
   
   $obj = new \AliasClass();
   echo $obj->hello();
?> 

Output

This will generate the below output −

Hello from MyNamespace\MyClass!

Example 3

In this PHP example, we create an alias for a class using the class_alias() function with a completely different class name.

<?php
   // Define an original class here
   class OriginalClass {
      public function meet() {
          return "Hello from OriginalClass! Nice to Meet You.";
      }
   }
  
   class_alias('OriginalClass', 'DifferentClass');
  
   $obj = new DifferentClass();
   echo $obj->meet();
?> 

Output

This will create the below output −

Hello from OriginalClass! Nice to Meet You.

Example 4

In the following example, we are using the class_alias() function and check if the class alias has been created using the if-else block.

<?php
   // Define an original class here
   class ExampleClass {
      public function greet() {
          return "Greetings from ExampleClass!";
      }
   }
  
   $aliasCreated = class_alias('ExampleClass', 'AliasClass');
   if ($aliasCreated) {
      $obj = new AliasClass();
      echo $obj->greet();
   } else {
      echo "Alias creation failed.";
   }
?> 

Output

Following is the output of the above code −

Greetings from ExampleClass!