PHP Quick Scripting Reference

CHAPTER 12

Static

The static keyword can be used to declare properties and methods that can be accessed without having to create an instance of the class. Static (class) members only exist in one copy, which belongs to the class itself, whereas instance (non-static) members are created as new copies for each new object.

class MyCircle{  // Instance members (one per object)  public $r = 10;  function getArea() {}    // Static/class members (only one copy)  static $pi = 3.14;  static function newArea($a) {}}

Static methods cannot use instance members since these methods are not part of an instance. They can however use other static members.