Re: MTA with Thread Pool API

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"Scherbina Vladimir" <vladimir.scherbina@xxxxxxxxxxxx> wrote in message
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What's wrong with NOT calling CoUninitialize?

--
Vladimir


"Sarge" <Sarge@xxxxxxxxxxxxxxxxx> wrote in message
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"Scherbina Vladimir" <vladimir.scherbina@xxxxxxxxxxxx> wrote in message
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Hello, Sarge.

<Sarge@xxxxxxxxxxxxxxxxx> wrote in message
news:efZPZUZiGHA.1508@xxxxxxxxxxxxxxxxxxxxxxx
I have a C/C++ multi-threaded socket server app that uses OLE DB for
it's SQL activity. The app uses a completion port for socket I/O, but
doesn't properly implement connection pooling with OLE DB. Each thread
of the process holds on to it's own connection object (IDBInitialize),
which I know is wrong.

So I'm rewriting this app to maintain one IDataInitialize object, and
create the IDBInitialize objects on the fly, using the same connection
string. Hopefully, this won't add too much overhead, but it's what the
Microsoft technical article says to do for proper connection pooling.

Anyway, my question is related to CoInitializeEx(MTA) /
CoUninitialize() in regards to the thread pool API. I really like
using this API - QueueUserWorkItem(), BindIoCompletionCallback(),
RegisterWaitForSingleObject(), etc.

The problem is that Windows manages these threads, so I don't have the
opportunity to call CoInitializeEx / CoUninitialize. Using Thread
Local Storage, I can flag whether or not the thread has called
CoInitializeEx, but I still have no opportunity to call CoUninitialize.

The SDK is very clear that you must call the CoInit functions once per
thread that uses COM. I thought about moving all the code into a DLL,
and using THREAD_ATTACH and THREAD_DETACH, but the SDK also says *not*
to call the CoInit functions from DLLMain().

Does this mean that I'm stuck with my own completion ports, or is there
some way that I can use the thread pool API?

Thanks for your time.

--Sarge



I may suggest to use own thread pool and control all CoInitialize(),
CoUnitialize() calls, or miss the call of CoUninitialize() when your
worker threads are done - I guess this will be when your application
terminates so at this point usless think (but remember that this is a
good style) about resources.

--
Vladimir


Vladimir, I was afraid of that. I can do my own thread pool and handle
the CoInit functions from my own worker threads. Since I'm writing those
threads, it's easy to issue CoInitializeEx at the top and CoUninitialize
at the bottom.

I sure will miss the convenience of the thread pool API. :-(

--Sarge




A good thread pool grows and shrinks on activity demand. If all my threads
were persistent for the life of the program, then I wouldn't worry about
calling CoUninitialize.

--Sarge


.

Relevant Pages

  • Re: MTA with Thread Pool API
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    (microsoft.public.win32.programmer.kernel)
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