When is a class's destructor called?

[Mike]

On Sunday, 29 December 2013 at 06:53:08 UTC, Mike Parker wrote:
> On 12/29/2013 2:03 PM, Mike wrote:
>
>>
>> x's destructor never gets called.  What do I need to implement 
>> to have
>> the destructor called when x goes out of scope?
>>
>
> Class destructors are not called when an object goes out of 
> scope. They are called by the garbage collector only when 
> memory needs to be reclaimed or during the cleanup cycle during 
> app shutdown.

Ok, I understand that, but since I don't have a garbage 
collector, what must I implement to call the destructor when it 
goes out of scope?

Another way of asking the question is: How does the garbage 
collector know when something has gone out of scope and is 
therefore safe to collect?  And where is that implemented in the 
runtime?