Clarification on ZVals
- by Beachhouse
I was reading this: http://www.dereleased.com/2011/04/27/the-importance-of-zvals-and-circular-references/
And there's an example that lost me a bit.
$foo = &$bar;
$bar = &$foo;
$baz = 'baz';
$foo = &$baz;
var_dump($foo, $bar);
/*
string(3) "baz"
NULL
*/
If you’ve been following along, this should make perfect sense. $foo
is created, and pointed at a ZVal location identified by $bar; when
$bar is created, it points at the same place $foo was pointed. That
location, of course, is null. When $foo is reassigned, the only thing
that changes is to which ZVal $foo points; if we had assigned a
different value to $foo first, then $bar would still retain that
value.
I learned to program in C. I understand that PHP is different and it uses ZVals instead of memory locations as references. But when you run this code:
$foo = &$bar;
$bar = &$foo;
It seems to me that there would be two ZVals. In C there would be two memory locations (and the values would be of the opposite memory location).
Can someone explain?
