PHP - Destructors

A destructor is a special method of a class which destructs or deletes an object and automatically executed when the object goes out of scope. An object goes out of scope when:

• the function containing object ends.
• the program ends.
• a block containing local object variable ends.
• a delete operator is called for an object.

Create Destructor

The PHP __destruct() function is a reserved built-in function also called class destructor. It is automatically executed when the object goes out of scope. Please note that it starts with two underscores (__). A class can have only one destructor. When a destructor is not specified in a class, compiler generates a default destructor and inserts it into the code.

Syntax

function __destruct() {
  statements;
}

Example:

In the example below, a class called person is created. A constructor and destructor are also created. The destructor prints a message before deleting the object and called automatically when a object goes out of scope (program ends in this example).

<?php
class person {
  private $name;
  private $city;
  function __construct($name, $city) {
    $this->name = $name;
    $this->city = $city;
    echo $this->name." lives in ".$this->city.".\n";   
  }
  function __destruct() {
    echo "Destructor invoked for: ".$this->name."\n";
  }   
};

$p1 = new person('John', 'London');
$p2 = new person('Marry', 'New York');
?>

The output of the above code will be:

John lives in London.
Marry lives in New York.
Destructor invoked for: Marry
Destructor invoked for: John