How can weak references be implemented in PHP to avoid memory leaks caused by cyclic references?

Weak references in PHP can be implemented using the WeakReference class. This class allows you to create a reference to an object without preventing it from being garbage collected when there are no strong references left. By using weak references, you can avoid memory leaks caused by cyclic references in PHP.

// Create a weak reference to an object
$object = new stdClass();
$weakRef = WeakReference::create($object);

// Access the object from the weak reference
$retrievedObject = $weakRef->get();

// Check if the object still exists
if ($retrievedObject !== null) {
    // Object is still available
    echo "Object is still available\n";
} else {
    // Object has been garbage collected
    echo "Object has been garbage collected\n";
}