PHP：通过引用传递数组失败

I've the following code function:

function foo(&$vett) {

    $vettore = $vett;

    $vettore[] = "ciao";

    var_dump($vettore);
}

$v = array();

foo($v);

var_dump($v);

When I dump the final array is empty. Have you any idea of what could be?

Because $v never modified. Inside the function you assign the variable into another variable. So nothing ever happen to the old $vett

try something like:

function foo(&$vett) {
    $vett[] = "ciao";
    echo __LINE__;
    var_dump($vett);
}

$v = array();
foo($v);
var_dump($v);

Correct version is:

function foo(&$vett) {
    $vett[] = "ciao";
}

$v = array();
foo($v);
var_dump($v);