Re: [Boost-users] [thread] thread_specific_ptr is not initializedwith NULL

Subject: Re: [Boost-users] [thread] thread_specific_ptr is not initializedwith NULL
From: Michael Gopshtein (mgopshtein_at_[hidden])
Date: 2009-06-08 00:45:47

Thanks.

That's not the case with "native" TLS support (it promises to zero out all 
values in released slot), but it's good to know that this is undefined for 
thread_specific_ptr.

BTW, is it because such pattern of use is not considered interesting? For 
example, in our application there are "Database" objects which are created 
and destroyed dynamically, and each Database has a unique connection per 
thread, which are stored in the TLS. The connections are also stored in 
seperate lists, and are released when the Database is no longer in use - so 
the "default" behavior of the native API (both Win32 and pthreads) is OK 
with us.

Anyway, thanks again for the info.
Michael

"Anthony Williams" <anthony.ajw_at_[hidden]> wrote in message 
news:874ouru5pm.fsf_at_dell.justsoftwaresolutions.co.uk...
> "Michael Gopshtein" <mgopshtein_at_[hidden]> writes:
>
>
> This is now undefined behaviour. If you destroy a thread_specific_ptr
> whilst any thread has a non-NULL value then you cannot rely on what
> happens subsequently with respect to any thread that tries to use that
> or a new thread_specific_ptr instance.
>

> Anthony
> -- 
> Author of C++ Concurrency in Action | http://www.manning.com/williams
> just::thread C++0x thread library   | http://www.stdthread.co.uk
> Just Software Solutions Ltd         | 
> http://www.justsoftwaresolutions.co.uk
> 15 Carrallack Mews, St Just, Cornwall, TR19 7UL, UK. Company No. 5478976