Re: can event handler call event source passed as connection point parameter?

"Xudong" <>
28 Sep 2006 09:39:10 -0700
What's weird here is that if I do a redundant QueryInterface on the
pointer for its own type, the code runs normal! The code is similar to

// event source in free threaded DLL
class CServer ... {
    Fire_OnSomeEvent(IServer* ptr) { // ATL generated
        HRESULT hr = Invoke(...);

    SomeMethod() {}

// event handler in apartment threaded EXE
class CClient ... {
    void __stdcall OnSomeEvent(IServer * ptr) {
        ptr->QueryInterface(IID_IServer, (void**)&ptr); // line X
        ptr->SomeMethod(): // line Y

With line X, everything works fine and line Y does call through
Without line X, I saw "0x0000005 access violation while writing" at
line Y if I turned on all exception for debugging, and the Invoke in
the Fire method returned 0x80010105.

Is this related to the threading issue? Any idea why line X workaround
the problem?

Thanks & regards,

Igor Tandetnik wrote: wrote:

If event source passes itself as parameter with Fire_OnSomeEvent(...),
can event handler OnSomeEvent(...) invokes its methods via the pointer
passed in?


I tried that but received error "0x80010105 The server
threw an exception" inside Fire_OnSomeEvent(...) at the time event
handler made such call.

You did something wrong: either the server or the client crashed for
some reason. There is no fundamental underlying problem with what you
are trying to do - there's a bug in your code somewhere.
With best wishes,
    Igor Tandetnik

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