> I'm using xml messages for various communications in my application.
> 
> The application is multithreaded and some of the more complicated 
> interactions have IXMLDOMDoc messages being handed from one thread to 
> another and destroyed by the other thread when done (the messages are 
> too large and numerous to be translating the whole DOM to string form 
> and back again).
> 
> I have a handle leak which I can demonstrate with the code below:
> 
> ===============================================================
> ===============================================================
> #include "msxml2.h" // Linker includes msxml2.lib
> 
> DWORD WINAPI TestThread(LPVOID blah)
> {
> 	CoInitialize(NULL); // +2 handles
> 
> 	CComPtr <IXMLDOMDocument> xmlDomDoc2;
> 	xmlDomDoc2.CoCreateInstance(L"MSXML2.DOMDocument.3.0", NULL, 
> CLSCTX_INPROC_SERVER); // +4 handles
> 	xmlDomDoc2.Release(); // -0 handles
> 
> 	CoUninitialize(); // -0 handles
> 
> 	return 0;
> }
> 
> 
> void SmartPointerXMLDOMDocTest()
> {
> 	// Start off with 44 handles
> 
> 	CoInitialize(NULL); // +9 handles
> 
> 	CComPtr <IXMLDOMDocument> xmlDomDoc1;
> 	xmlDomDoc1.CoCreateInstance(L"MSXML2.DOMDocument.3.0", NULL, 
> CLSCTX_INPROC_SERVER); // +20 handles
> 	xmlDomDoc1.Release(); // -0 handles
> 
> 	DWORD threadID = NULL;
> 	CreateThread(NULL, NULL, TestThread, NULL, 0, &threadID); // +1 
> handle
> 
> 	Sleep(5000); // Allow time for thread to complete (which it does).
> 
> 	CoUninitialize(); // -25 handles
> 
> 	// End with 55 handles
> }
> 
> ===================================================================
> ===================================================================
> 
> 
> Every time a new thread creates an IXMLDOMDoc it allocates handles which 
> are not cleaned up until every thread calls CoUninitialize.
> 
> You can't call CoUninitialize until your not going to use the IXMLDOMDoc 
> again.
> 
> This means that if _any_ thread holds onto one of these docs, then 
> _none_ of the other threads' handles are ever cleaned up.
> 
> This would be fine, but some parts of the app use XML for storage, not 
> just message passing, so they may never let go of their xml docs until 
> the app is finished.
> 
> At the rate my app passes messages, I can pick up about 50k handles in a 
> few minutes.
> 
> 
> I've been at this for weeks, so flames are fine as long as something 
> useful comes of it.
> 
> 
> -BB

I have the same problem.
I tried with MSXML2, 3, 4, 5 and 6 - but the problem still exists. It seems 4 semaphore handles are leaked everytime I CoCreate an MSXML DOM object and release it. There was an article which said that perhaps I should turn OFF the full garbage collection. I tried creating a NoFullGC registry DWORD value set to 1. No success. I am surprised that Microsoft has been keeping mum on the issue.
Way to go, Microsoft !!!

I am now forced to rearchitect my code in order to avoid creating too many DOM parser objects from a worker thread.

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