PHP Static class variables, inheritance, and garbage collection

Question

I am having some memory problems with a script that uses objects set up with inherited static variables like this.

class a
{
    public static $a = "a";
}

class b extends a
{
    private $instanceVar = 'hey';
    private $otherVar = 'you';

    public function DoStuff()
    {
        echo self::$a;
    }
}

then code that uses the classes like this

while(condition)
{
    $obj = new b();
    $obj -> DoStuff();
    unset($obj);
}

My question is, will unsetting obj trigger garbage collection and the unsetting of its instance variables since it also holds a reference to the the inherited static variable?

zerkms · Accepted Answer · 2012-11-22 02:55:40Z

2

unset in this code doesn't bring anything.

With and without it the object will be successfully collected when it's possible.

will unsetting obj trigger garbage collection

Not it won't. Garbage collector will be called automatically when it makes sense.

since it also holds a reference to the the inherited static variable

It doesn't. Objects don't hold references to a static properties.

answered Nov 22, 2012 at 2:55

zerkms

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Comments

Ruben Nagoga · Accepted Answer · 2012-11-22 06:41:40Z

-1

If you care so much about GC and have PHP >= 5.3.0 have a look to gc_collect_cycles and garbage collection in general

answered Nov 22, 2012 at 6:41

Ruben Nagoga

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