Weakref::acquire
(PECL weakref >= 0.1.0)
Weakref::acquire — Acquires a strong reference on that object
说明
public Weakref::acquire
( void
) : bool
Acquires a strong reference on that object, virtually turning the weak reference into a strong one.
The Weakref instance maintains an internal acquired counter to track outstanding strong references. If the call to Weakref::acquire() is successful, this counter will be incremented by one.
参数
此函数没有参数。
返回值
Returns TRUE if the reference was valid and could be turned into a strong
reference, FALSE otherwise.
范例
Example #1 Weakref::acquire() example
<?php
class MyClass {
public function __destruct() {
echo "Destroying object!\n";
}
}
$o1 = new MyClass;
$r1 = new Weakref($o1);
$r1->acquire();
echo "Unsetting o1...\n";
unset($o1);
$o2 = $r1->get();
$r1->release();
echo "Unsetting o2...\n";
unset($o2);
?>
以上例程会输出：
Unsetting o1... Unsetting o2... Destroying object!
Example #2 Nested acquire/release example
<?php
class MyClass {
public function __destruct() {
echo "Destroying object!\n";
}
}
$o1 = new MyClass;
$r1 = new Weakref($o1);
echo "Acquiring...\n";
$r1->acquire();
echo " Unsetting...\n";
unset($o1);
echo " Acquiring...\n";
$r1->acquire();
echo " Acquiring...\n";
$r1->acquire();
echo " Releasing...\n";
$r1->release();
echo " Releasing...\n";
$r1->release();
echo "Releasing...\n";
$r1->release();
?>
以上例程会输出：
Acquiring...
Unsetting...
Acquiring...
Acquiring...
Releasing...
Releasing...
Releasing...
Destroying object!