note 95522 added to language.oop5.references

Notes on reference: A reference is not a pointer. However, an object handle IS a pointer. Example: <?php class Foo { private static $used; private $id; public function __construct() { $id = $used++; } public function __clone() { $id = $used++; } } $a = new Foo; // $a is a pointer pointing to Foo object 0 $b = $a; // $b is a pointer pointing to Foo object 0, however, $b is a copy of $a $c = &$a; // $c and $a are now references of a pointer pointing to Foo object 0 $a = new Foo; // $a and $c are now references of a pointer pointing to Foo object 1, $b is still a pointer pointing to Foo object 0 unset($a); // A reference with reference count 1 is automatically converted back to a value. Now $c is a pointer to Foo object 1 $a = &$b; // $a and $b are now references of a pointer pointing to Foo object 0 $a = NULL; // $a and $b now become a reference to NULL. Foo object 0 can be garbage collected now unset($b); // $b no longer exists and $a is now NULL $a = clone $c; // $a is now a pointer to Foo object 2, $c remains a pointer to Foo object 1 unset($c); // Foo object 1 can be garbage collected now. $c = $a; // $c and $a are pointers pointing to Foo object 2 unset($a); // Foo object 2 is still pointed by $c $a = &$c; // Foo object 2 has 1 pointers pointing to it only, that pointer has 2 references: $a and $c; const ABC = TRUE; if(ABC) { $a = NULL; // Foo object 2 can be garbage collected now because $a and $c are now a reference to the same NULL value } else { unset($a); // Foo object 2 is still pointed to $c } ---- Server IP: 69.147.83.197 Probable Submitter: 119.247.149.171 ---- Manual Page -- http://www.php.net/manual/en/language.oop5.references.php Edit -- https://master.php.net/note/edit/95522 Del: integrated -- https://master.php.net/note/delete/95522/integrated Del: useless -- https://master.php.net/note/delete/95522/useless Del: bad code -- https://master.php.net/note/delete/95522/bad+code Del: spam -- https://master.php.net/note/delete/95522/spam Del: non-english -- https://master.php.net/note/delete/95522/non-english Del: in docs -- https://master.php.net/note/delete/95522/in+docs Del: other reasons-- https://master.php.net/note/delete/95522 Reject -- https://master.php.net/note/reject/95522 Search -- https://master.php.net/manage/user-notes.php