How can one verify if the memory space occupied by an object is truly released with the unset function in PHP?

When using the unset function in PHP to release memory occupied by an object, it doesn't guarantee immediate memory release. To verify if the memory space is truly released, you can use the memory_get_usage function before and after unsetting the object. If the memory usage decreases significantly after unsetting the object, it indicates that the memory space has been released.

// Create an object
$obj = new stdClass();

// Get initial memory usage
$initialMemory = memory_get_usage();

// Unset the object
unset($obj);

// Get memory usage after unsetting the object
$finalMemory = memory_get_usage();

// Check if memory usage decreased significantly
if ($finalMemory < $initialMemory) {
    echo "Memory space occupied by the object has been released.";
} else {
    echo "Memory space occupied by the object has not been released.";
}