php variable variables problem
<pre><code>$_POST['asdf'] = 'something';

function test() {
    // NULL -- not what initially expected
    $string = '_POST';
    echo '====';
    var_dump(${$string});
    echo '====';

    // Works as expected
    echo '++++++';
    var_dump(${'_POST'});
    echo '++++++';

    // Works as expected
    global ${$string};
    var_dump(${$string});

}

// Works as expected
$string = '_POST';
var_dump(${$string});

test();
</code></pre>

<p>I am not getting why such behaviour.. can anybody explain.. i need to know why such behaviours. i am actually not getting the code.. </p>
