文字
The WeakRef class
(PECL weakref >= 0.1.0)
简介
The WeakRef class provides a gateway to objects without preventing the garbage collector from freeing those objects. It also provides a way to turn a weak reference into a strong one.
类摘要
WeakRef {
public Weakref::__construct
( object
$object
) public bool Weakref::acquire
( void
)
public object Weakref::get
( void
)
public bool Weakref::release
( void
)
public bool Weakref::valid
( void
)
}范例
Example #1 WeakRef usage 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!
Table of Contents
- Weakref::acquire — Acquires a strong reference on that object
- Weakref::__construct — Constructs a new weak reference
- Weakref::get — Returns the object pointed to by the weak reference
- Weakref::release — Releases a previously acquired reference
- Weakref::valid — Checks whether the object referenced still exists