A few questions regarding memory management

[utexas_pjm]

I'm not able to find any reliable information of this subject, so I was wondering of any of you could help me out.  Most PHP applications are written for use within a webserver so the application is interpreted and executed then its memory is freed, this makes memory management not much of a concern for the developer.  However, I am in the early development stages of a daemon type PHP app (my recent post in the Future Contest Ideas thread sparked my curiosity) and I am now concerned with the possibility of memory leaks which brings me to my question:  Does PHP5 employ garbage collection?

 

In Java the garbage collection will release all memory on the heap which is no longer referenced by any references still in scope.  That is, I can do something like this without eventually running out of memory:

 

//...
public void listen()
{
  Foo fooInstance;
  while(true){
    fooInstance = new Foo();
    fooInstance.doSomething();
    fooInstance = null;
  }
}
//...

 

Would this work in PHP?  Or do I need to explicitly release the memory on the heap ala C?

 

If someone could lend me some insight, or even better, point me in the direction of some reliable documentation I would greatly appreciate it.

 

Best,

 

Patrick

[fert]

PHP does have garbage collection

[utexas_pjm]

Thanks fert,

 

I finally sucked it up and ran some tests on my own.  PHP (5.1) reacts as I expected it would (should).

 

<?php
class Foo
{
private $largeArray;

public function __construct()
{
	for($i = 0; $i < 10000; ++$i){
		$this->largeArray[] = rand(10000, 1000000);
	}
}


public function __destruct()
{
	print "Poof\n";
} 
}

for($i = 0; $i < 3; ++$i){

print "Initial\t\t\t" . memory_get_usage()/1024 . "k\n";

$fooInstance = new Foo();

print "After instanciation\t" . memory_get_usage()/1024 . "k\n";
}
?>

 

Results in:

 

Initial                 43.3984375k
After instanciation     654.5625k
Initial                 654.671875k
Poof
After instanciation     668.640625k
Initial                 668.640625k
Poof
After instanciation     668.640625k
Poof

 

Best,

 

Patrick