Weakref::__construct

(PECL weakref >= 0.1.0)

Weakref::__construct — Constructs a new weak reference

说明

public Weakref::__construct ( object $object )

Constructs a new weak reference.

参数

object: The object to reference.

返回值

没有返回值。

范例

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!