Re: [boost] Re: Thread Lib and DLL

From: David Abrahams (dave_at_[hidden])
Date: 2003-03-29 10:15:46

"William E. Kempf" <wekempf_at_[hidden]> writes:

> Russell Hind said:
>> I'd been wondering this, and heard about TLS issues.  The issues are
>> only on Windows it appears.  Search for the thread
>>
>> "Fwd: Thread-Local Storage (TLS) and templates" by Greg Colvin on
>> 18/02/2003
>>
>> Specifically, the many posts by William Kempf and Edward Diener discuss
>> the problems on windows with TLS cleanup.
>>
>> I do have a question on this issue:  If this problem is only to do with
>> TLS cleanup when a thread exits, then if all threads are created when
>> the program starts and only destroyed when the program exited, then, in
>> practice, could this really be an issue?  I.e. if we only work like
>> this, could building thread as a static lib cause problems providing
>> that we don't let threads exit in the middle of the program?  We're
>> currently really trying to stay clear of any DLLs.
>
> Theoretically at least, I don't see why this would cause a problem.  You
> intentionally leak, but the leak is benign since it occurs only right
> before the application exits.  But most users won't code this way, nor do
> I want to have to deal with the support requests/questions this would
> cause.  So, unless you have some suggestion as to how I can enable this
> usage with out causing confusion, I'm not sure I'd care to re-enable
> static builds.  But you could probably fairly easily hack things to build
> that way yourself.

I don't really understand the issues here, but I was wondering if you
could reclaim "leaked" TLS resources lazily somehow, by looking for
unused TLS the next time new TLS is requested.  Just a thought...

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com