Constructors and Destructors

Constructor : 

void __construct ([ mixed $args = “” [, $... ]] )

PHP 5 allows developers to declare constructor methods for classes. Classes which have a constructor method call this method on each newly-created object, so it is suitable for any initialization that the object may need before it is used.

Note: Parent constructors are not called implicitly if the child class defines a constructor. In order to run a parent constructor, a call to parent::__construct() within the child constructor is required. If the child does not define a constructor then it may be inherited from the parent class just like a normal class method (if it was not declared as private).

Destructor :

void __destruct ( void )

PHP 5 introduces a destructor concept similar to that of other object-oriented languages, such as C++. The destructor method will be called as soon as there are no other references to a particular object, or in any order during the shutdown sequence.

Like constructors, parent destructors will not be called implicitly by the engine. In order to run a parent destructor, one would have to explicitly call parent::__destruct() in the destructor body. Also like constructors, a child class may inherit the parent’s destructor if it does not implement one itself.

The destructor will be called even if script execution is stopped using exit(). Calling exit() in a destructor will prevent the remaining shutdown routines from executing.

Note: Destructors called during the script shutdown have HTTP headers already sent. The working directory in the script shutdown phase can be different with some SAPIs (e.g. Apache).

Note: Attempting to throw an exception from a destructor (called in the time of script termination) causes a fatal error.

Example :

<?php
class MyClass {
function __construct() {
print “In constructor\n”;
$this->name = “MyClass”;
}

function __destruct() {
print “Destroying ” . $this->name . “\n”;
}
}

 

data source : php