PHP garbage collection and functions

Question

I'm using PHPQuery (HTML parser) in a loop, and unsetting the previous document each time by using phpQuery::unloadDocuments(). The loop simplifies to:

while(...){
  $doc="parsed stuff";
  ...
  unset($doc);
}

However, there's memory leak in this because the script runs out of memory after a while. After searching online, someone recommended that to avoid memory leak, I should wrap it in a function, so I changed it to this:

function r(){
  $doc="parsed stuff";
  ...
  unset($doc);
}
while(...)
  r();

Now, the memory leak stopped. Why is this?

Answer 1

See this http://php.net/manual/en/language.references.unset.php, is has good example there.