Re: [Quantlib-users] ObservableSettings is deleted early than Observables.

[Eric E. <eri...@re...>]

OK, I will take a crack at it before the next release.  I hope that I 
can recreate the error somehow, otherwise it will be hard to test the fix.


Kind Regards,
Eric


On 11/14/20 9:25 AM, SX L wrote:
> I don't have a github account yet, and I am an old fashion coder still 
> using svn. However, the change is simple as below. If I were to go 
> into multithread later, I would dump or re-design Singleton pattern, 
> which is notorious for multithread.
>
> Index: ql/patterns/singleton.hpp
> ===================================================================
> --- ql/patterns/singleton.hpp   (revision 130)
> +++ ql/patterns/singleton.hpp   (working copy)
> @@ -160,7 +160,7 @@
>      T& Singleton<T>::instance() {
>
>          #if (QL_MANAGED == 0) && !defined(QL_SINGLETON_THREAD_SAFE_INIT)
> -        static std::map<ThreadKey, ext::shared_ptr<T> > instances_;
> +        static T instances_;
>          #endif
>
>          // thread safe double checked locking pattern with atomic 
> memory calls
> @@ -185,9 +185,7 @@
>          ThreadKey id = 0;
>          #endif
>
> -        ext::shared_ptr<T>& instance = instances_[id];
> -        if (!instance)
> -            instance = ext::shared_ptr<T>(new T);
> +        T* instance = &instances_;
>
>          #endif
>
> ------------------------------------------------------------------------
> *From:* Eric Ehlers <eri...@re...>
> *Sent:* Wednesday, November 11, 2020 4:35 AM
> *To:* SX L <han...@ho...>
> *Cc:* qua...@li... 
> <qua...@li...>
> *Subject:* Re: [Quantlib-users] ObservableSettings is deleted early 
> than Observables.
>
> Hi Philip,
>
> Would you be willing to submit a pull request?
>
> Regards,
> Eric
>
> On 11/10/20 5:21 AM, SX L wrote:
>> Hi Eric,
>>
>> Thanks for looking into this issue. Yes, I identified the issue in my 
>> windows x64 debug version. The issue could be hard to reproduce since 
>> my release version gives me normal exit code. It really depends on 
>> the sequence of calling dtors of those shared pointers at exit.
>>
>> So I would suggest moving away from shared pointers in Singletons. 
>> Create a singltonDestroyer or use static instances.
>>
>> Get Outlook for Android <https://aka.ms/ghei36>
>>
>> ------------------------------------------------------------------------
>> *From:* Eric Ehlers <eri...@re...> 
>> <mailto:eri...@re...>
>> *Sent:* Monday, November 9, 2020, 11:42 PM
>> *To:* SX L
>> *Cc:* qua...@li... 
>> <mailto:qua...@li...>
>> *Subject:* Re: [Quantlib-users] ObservableSettings is deleted early 
>> than Observables.
>>
>> Hi Philip,
>>
>> I tried unsuccessfully to recreate the error.  You did not say which 
>> operating system you are using but you mention "debug version" which 
>> sounds like visual studio so I tested it on Windows - I'm using 
>> Visual Studio 2019 on 64-bit WIndows 10.  I built it using "Debug 
>> (static runtime)" x64 and I ran ClientCppDemo and it behaves as I 
>> expected (no access violation).  Anything else I can try to recreate 
>> the error?
>>
>> I have not examined the code but your remarks sound sensible to me.  
>> What resolution would you suggest?
>>
>> Regards,
>> Eric
>>
>> On 10/7/20 6:43 AM, SX L wrote:
>>> I was trying the Quantlib Addin. The QLADemo exits abnormally in the 
>>> debug version with an access violation exception. It turned out to 
>>> be the case that ObervableSettings is deleted earlier than some 
>>> observer and observables at exit. So in the dtor of the observer, 
>>> ObservableSettings is called to check if update is deferred, hence 
>>> causing the exception. I feel it's unsafe to use shared pointers 
>>> inside a singleton. Any suggestion? Thanks.
>>>
>>> Regards,
>>>
>>> Philip
>>>
>>>
>>> Get Outlook for Android <https://aka.ms/ghei36>
>>>
>>>
>>> _______________________________________________
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>>> Qua...@li...  <mailto:Qua...@li...>
>>> https://lists.sourceforge.net/lists/listinfo/quantlib-users
>>