Re: [xml] Windows threading issues

[Daniel Veillard <veillard redhat com>]

On Thu, Jul 10, 2003 at 11:33:46AM -0400, Jesse Pelton wrote:
> I'm hoping someone on the list has enough experience with Windows
> multithreading and libxml (Igor? Stephane?) to help with a problem I'm
> seeing.

  Honnestly I'm a bit lost there, so yes if someone else can check this
I would be grateful.

> The situation is this: I'm using libxml 2.5.8 (statically linked) in an
> ISAPI DLL running under IIS 5, and I'm not sure how to build the library so
> it cleans up its thread-local "global" data correctly. I started with
> LIBXML_STATIC defined (because it seemed like the right thing to do, since
> I'm statically linking to the library), but this often crashes at exit.
> (There's a cleanup thread that calls WaitForSingleObject(), but by the time
> the wait returns, the thread's code has been unloaded, leading to an access
> violation.) If I leave LIBXML_STATIC undefined, theory has it that libxml's
> DllMain() will use DLL_THREAD_DETACH and DLL_PROCESS_DETACH calls to clean
> up properly - but then libxml's DllMain() conflicts with my own. If I were
> to remove libxml's DllMain(), my own DllMain() couldn't clean up, because it
> wouldn't have access to required static variables.
>
> It looks to me like libxml is not presently designed to work as a library
> statically linked into a DLL. If I'm right, a solution might be to make
> libxml's DllMain() conditional on another preprocessor constant and add a
> cleanup function that either libxml's DllMain() or another DllMain() could
> call.
>
> So, my questions:
> 1) Does my assessment that libxml needs a patch to work in my scenario make
> sense?
> 2) If so, does my solution make sense, or is there a better approach?
>
> I'm happy to attempt a patch if necessary.

  I wonder how much this is related to the Windows extra token we planned
to add to the includes (Sorry about this Igor, I realize I never answered 
<grin/> to your mail asking for feedback).

Daniel

-- 
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