Php – how to pass by reference a class var to a global var in PHP

pass-by-referencephp

please tell me theres a way around this…

$my_var = 'hello';

class Test{

    private $my_var;
    private $my_internal_var = 'if you see this it works!';

    function __construct(){
        global $my_var;

        $this->my_var = &$my_var;
    }

    function get_my_var(){
        return $this->my_var;
    }

    function set_my_var($value){
        $this->my_var = $value;
    }

    function set_my_var_to_internal_reference(){
        //this line should make $my_var in root, $my_var in this object, and $my_var in
        //all external functions point to $my_internal_var.
        $this->my_var = &$this->my_internal_var;
    }
}


function get_my_var(){
    global $my_var;

    return $my_var;
}

function set_my_var($value){
    global $my_var;

    $my_var = $value;
}


$my_obj = new Test();

echo '<h2>set default starting value</h2>';
echo 'obj : '.$my_obj->get_my_var().'<br>'; //echoes 'hello' - this is ok
echo 'func: '.get_my_var().'<br>'; //echoes 'hello' - this is ok
echo 'root: '.$my_var.'<br>'; //echoes 'hello' - this is ok

set_my_var('hello world!');

echo '<h2>set to value by function</h2>';
echo 'obj : '.$my_obj->get_my_var().'<br>'; //echoes 'hello world!' - this is ok
echo 'func: '.get_my_var().'<br>'; //echoes 'hello world!' - this is ok
echo 'root: '.$my_var.'<br>'; //echoes 'hello world!' - this is ok

$my_obj->set_my_var('hello world again!');

echo '<h2>set to value by object method</h2>';
echo 'obj : '.$my_obj->get_my_var().'<br>'; //echoes 'hello world again!' - this is ok
echo 'func: '.get_my_var().'<br>'; //echoes 'hello world again!' - this is ok
echo 'root: '.$my_var.'<br>'; //echoes 'hello world again!' - this is ok

$my_obj->set_my_var_to_internal_reference();

echo '<h2>set to object internal reference</h2>';
echo 'obj : '.$my_obj->get_my_var().'<br>'; //echoes '      ' - this is NOT ok. should be 'if you see this it works!'
echo 'func: '.get_my_var().'<br>'; //echoes 'hello world again!' - this is NOT ok. should be 'if you see this it works!'
echo 'root: '.$my_var.'<br>'; //echoes 'hello world again!' - this is NOT ok. should be 'if you see this it works!'

Thanks!!

Best Solution

This is NOT ok as is. You should use a wrapper object in OO enviorment, and don't use global vars, they are sucks. Example:

class My_Registry{
    private $registry = array();

    public function set_var($key, $var){
        $this->registry[$key] = $var;
        return $this;
    }

    public function get_var($key){
       if(isset($this->registry[$key]){
           return $this->registry[$key]
       }else{
           return false;
       }
    }
}

Or something like this, you can add error handling, privileges, etc.

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