Re: [boost] Re: Weak ref. via atomicity (RE: Smart pointers:...)

From: Pavel Vasiliev (pavel_at_[hidden])
Date: 2003-02-11 13:04:00

Alexander Terekhov wrote:

> Pavel Vasiliev wrote:
> [...]
>> Thread A, in release_strong:
>>        atomic_decrement(&strong_count) == 0,
>>        enter strong_refs_lost(),
>>        lock

> ACK.

>> Thread B, in acquire_strong_from_weak: ....

> NAK.

>   Thread B, in release_weak:
>          atomic_decrement(&weak_count) == 0,
>> Thread A, in strong_refs_lost:
>>        see strong_count == 0,
>          acquire_weak() --> weak_count == 1,
>          ...
>          enter release_weak(),
>          atomic_decrement(&weak_count) == 0,
>   Thread B, enter weak_refs_lost():
>          ... 
>          destruct_self()
>   Thread A, enter weak_refs_lost():

> WHACK!

Ok, indeed "WHACK!" :-)
But my idea with initial weak_count == 0 in any case was not good.
Please see my previous reply that fixes it, now reading not
"aesthetic feelings" but "ordinary correctness". (Hope to have this
correctness now.)

Pavel