PHP garbage collection and functions

Question

I use PHPQuery (HTML parser) in a loop and each time undoing the previous document using phpQuery::unloadDocuments() . The cycle is simplified to:

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

However, a memory leak occurs due to a lack of script memory after a while. After searching the Internet, someone recommended that in order to avoid memory leak, I should wrap it in a function, so I changed it to the following:

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

Now the memory leak has stopped. Why is this?

Answer 1

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