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(PECL weakref >= 0.1.0)
Weakref::__construct — Constructs a new weak reference
$object
)Constructs a new weak reference.
object
The object to reference.
没有返回值。
Example #1 Weakref::__construct() example
<?php
class MyClass {
public function __destruct () {
echo "Destroying object!\n" ;
}
}
$o1 = new MyClass ;
$r1 = new Weakref ( $o1 );
if ( $r1 -> valid ()) {
echo "Object still exists!\n" ;
var_dump ( $r1 -> get ());
} else {
echo "Object is dead!\n" ;
}
unset( $o1 );
if ( $r1 -> valid ()) {
echo "Object still exists!\n" ;
var_dump ( $r1 -> get ());
} else {
echo "Object is dead!\n" ;
}
?>
以上例程会输出:
Object still exists! object(MyClass)#1 (0) { } Destroying object! Object is dead!