PHP在类对象数组中取消设置类对象会调用所有类对象的析构吗？

I have an array of Client class objects stored in a PHP array. Sometimes I need to unset() one of those objects in the array and I don't want to have to worry about explicitly closing the socket connection. I want __destruct() to do that for me.

class A{

    private $id;

    public function __construct( $id ){
        $this->id = $id;
    }

    public function __destruct(){
        echo "Calling destruct on " . $this->id . ".
";
    }

}

$array = array();

for($i=0;$i<5;$i++){
    $array[$i] = new A($i);
}

unset($array[3]);

print_r($array);

The destructor is fired as it should for the element we're destroying. But then every other destructor in the array is called even though the elements are not being destroyed. Why?

Calling destruct on 3.
Array
(
    [0] => A Object
        (
            [id:A:private] => 0
        )

    [1] => A Object
        (
            [id:A:private] => 1
        )

    [2] => A Object
        (
            [id:A:private] => 2
        )

    [4] => A Object
        (
            [id:A:private] => 4
        )

)
Calling destruct on 0.
Calling destruct on 1.
Calling destruct on 2.
Calling destruct on 4.

Why is this happening and what alternatives do I have?

If $array goes out of scope, then the rest of the objects will be destroyed, too.

It looks like that is happening. You see your destruct trace message, then your print_r() output, then the rest of the objects destruct.