Private vs Private Static

Question

I always use private $MyVar = false; when declaring private variables which only that specific class can use. But recently i saw some examples where people use private static $MyVar = false;.

I don't get it, what's the difference? Both of them can only be used inside that class, so whats the point in adding static?

A `static` class property is always the same value for all instances of the class, and even exists if there are no instances (when it can be accessed from static methods) - [PHP Docs](http://www.php.net/manual/en/language.oop5.static.php) It has no connection with visibility (private/public/protected) at all — Mark Baker, Aug 24 '14 at 13:49
I found the answer here http://stackoverflow.com/questions/1957629/how-to-access-a-private-member-inside-a-static-function-in-php?rq=1 — Adrao, Aug 24 '14 at 13:59

score 0 · Answer 1 · answered Aug 24 '14 at 16:32

Compare:

A private instance variable named x:

class Foo {
    private $x = 0;
    public function Foo() {
        echo ++$this->x . ',';
    }
}

new Foo();
new Foo();

The output is 1,1,.

A private static variable named x:

class Bar {
    private static $x = 0;
    public function Bar() {
        echo ++self::$x . ',';
    }
}

new Bar();
new Bar();

The output is 1,2,.

Private vs Private Static

1 Answers1