To clear up that confusion about public and public static access in PHP

Sep 19, 2008 php

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Apparently, a few programmers I know have been getting confused about access of public, public static variables in PHP classes. I’ve written this example code with the following comments to explain what will work - and what won’t.

class TEST
{
  /** public variable **/
  public $pubvar = 'pubvar';
 
  /** static public variable **/
  public static $pubvarstatic = 'pubvarstatic';
 
  public function __construct()
  {
    /** this works **/
    var_dump($this->pubvar);
 
    /** this also works **/
    var_dump(self::$pubvarstatic);
 
    /** this would not - no error **/
    var_dump($this->pubvarstatic);
  }
 
  public static function statictest()
  {
    /** this works - static accessing a static **/
    var_dump(self::$pubvarstatic);
 
    /**
     * this does not work - static has no business accessing a non static class var
     * generates error:
     * Fatal error:  Access to undeclared static property:  TEST::$pubvar
     */
    var_dump(self::$pubvar);
  }
}
print "<pre>";
 
/** for testing __construct() **/
new TEST;
 
/** this works - public static access **/
var_dump(TEST::$pubvarstatic);
 
/** for testing static method statictest() **/
TEST::statictest();