# The WeakMap class

(PECL weakref >= 0.2.0)

## Introduction

## Class synopsis

WeakMap implements Countable , ArrayAccess , Iterator {
/* Methods */
public __construct ( )
public count ( ) : int
public current ( ) : mixed
public key ( ) : object
public next ( ) : void
public offsetExists ( object `$object` ) : bool
public offsetGet ( object `$object` ) : mixed
public offsetSet ( object `$object` , mixed `$value` ) : void
public offsetUnset ( object `$object` ) : void
public rewind ( ) : void
public valid ( ) : bool
}

## Examples

Example #1 Weakmap usage example

`<?php
$wm = new WeakMap();
$o = new StdClass;
class A {
public function __destruct() {
echo "Dead!\n";
}
}
$wm[$o] = new A;
var_dump(count($wm));
echo "Unsetting..\n";
unset($o);
echo "Done\n";
var_dump(count($wm));`

The above example will output:

    int(1)
    Unsetting..
    Dead!
    Done
    int(0)

## Table of Contents

- WeakMap::__construct — Constructs a new map
- WeakMap::count — Counts the number of live entries in the map
- WeakMap::current — Returns the current value under iteration
- WeakMap::key — Returns the current key under iteration
- WeakMap::next — Advances to the next map element
- WeakMap::offsetExists — Checks whether a certain object is in the map
- WeakMap::offsetGet — Returns the value pointed to by a certain object
- WeakMap::offsetSet — Updates the map with a new key-value pair
- WeakMap::offsetUnset — Removes an entry from the map
- WeakMap::rewind — Rewinds the iterator to the beginning of the map
- WeakMap::valid — Returns whether the iterator is still on a valid map element