Reference detection in array from another function

Question

So I\'m using the pin method, but the reference is detected one level too late:

$pin = time();

function wrap($arr){
  test($arr);
}

function test(&$arr         


        

Answer 1

function wrap($arr){ test($arr); }
/// ...
wrap($array);

Your wrap() function allocates new memory block for $arr. When you calling test() function within wrap()s body, it takes reference of $arr memory block, but not an $arrays memory block, because $arr is a copy of $array and PHP memory management system stores them separately.

---

There is a universal reference spotting function:

function is_equal_refs(&$a, &$b){
    $buffer = $a;          // saving current value in temporary variable

    $a = md5(time());      // assigning new value to memory block, pointed by reference

    $result = ($a === $b); // if they're still equal, then they're point to the same place.

    $a = $buffer;          // restoring value

    return $result;        // returning result
}

So, lets do some testing:

Shows:

1   // < $arr
2
3
1   // < $array
2
3
ref // < $array doubled -> reference found

The reason of such behavior is $arr[3] contains reference for $arrays memory block, but not reference of itself's memory block.

Lets remove a $array[] = &$array; row, and modify wrap() function to check:

function wrap($arr){
    $arr[] = &$arr;

    test($arr);
}

And result would be:

1   // < $arr
2
3
ref // < $arr doubled -> reference found

Because $arr not points to $array, but to itself in $arr[3]. So, in your code there are different references you want to spot.

---

CONCLUSION: What you want to achieve is breaking out PHP memory management rules.

---

UPDv1:

Need to seek a workaround, to restore $array reference in a wrap() function scope.

1) A "bad" / "globals" practice:

Which shows:

1
2
3
ref

---

2) A "wrap everything in array or object" practice: (prefered and reliable)

 &$array)); // trick

print PHP_EOL;

$ring      = array(1, 2, 3, array(4, 5, 6));
$ring[3][] = &$ring;

wrap(array(REF_MARKER => &$ring)); // trick

print PHP_EOL;

$test = array('a', 'b', 'c');
$ring = array(1, 2, 3);

$ring[] = &$test;
$test[] = &$ring;

wrap(array(REF_MARKER => &$ring)); // trick

print PHP_EOL;

wrap(range(1, 5)); // normal

print PHP_EOL;

$test = array(1, 2, 3, array(1, 2, 3), 4, array(5, 2, 3), array(6, array(1, 2, 3), 7), array(1, 2, 3));

wrap($test); // normal

print PHP_EOL;

$test[]    = &$test;
$test[3][] = &$test;
$test[5][] = &$test[3];

wrap(array(REF_MARKER => &$test)); // trick
?>

Shows:

1 2 3 ref
1 2 3 4 5 6 ref
1 2 3 a b c ref
1 2 3 4 5
1 2 3 1 2 3 4 5 2 3 6 1 2 3 7 1 2 3
1 2 3 1 2 3 ref 4 5 2 3 ref 6 1 2 3 7 1 2 3 ref