Re: win32 message queue, multithreading, COM problem

"Albert Gomez" <>
Fri, 8 Dec 2006 12:37:14 -0800
I have determined that the problem arises after the instantiation of the COM

 hr=CoGetClassObject(CLSID_MyServer,CLSCTX_INPROC_SERVER,NULL,IID_IClassFactory,(void**)&pCf);I am thinking that I am not fully undertanding how to use a Single ThreadedApartment COM object with a client.If the client is multithreaded, and the STA COM object is created in aseparate thread, can this type of behavior result?"Albert Gomez" <> wrote in messagenews:%23Pv48eMGHHA.420@TK2MSFTNGP02.phx.gbl...> Hello,> I am trying to get a simple program working that involves a consoleapplication that spawns a thread; the thread will call an ATL COM object,create a small dialog box and windows message queue, and loop until the userpresses the escape key. The COM object is created using STA model...I amcalling it from child thread only.>> I do not understand what is wrong here. When I hit the escape key, theprogram goes into an infinite loop starting at the cleanup of the thread(CLEANUP02), runs past the ReleaseMutex call, and then resumes back atCLEANUP02.>> The COM object was from a codeproject application Systemtraydemo.>> Here is my source code:>> #ifndef _MT>> #define _MT>> #endif>>>> #include <windows.h>>> #include "stdio.h">> #include <iostream>>> #include "process.h">>>> #define INITGUID>> #include <objbase.h>>> #include "SystemTrayDemo.h">> #include "resource.h">> // global flag>> bool bDone = false;>>>>>> // this function is called by a new thread>> unsigned _stdcall InputThreadProc(LPVOID lpMutex)>> {>> HANDLE hMutex = (HANDLE) lpMutex;>>>> // create the dialog window>> HWND hWnd = ::CreateDialog(NULL,MAKEINTRESOURCE(IDD_DIALOG),NULL,NULL);>> if ( hWnd!=NULL )>> {>> // show dialog>> ShowWindow(hWnd,SW_SHOW);>> }>> else>> {>> printf("Failed to create dialog\n");>> return -1;>> }>> // message loop to process user input>>>> // Create Icon here>> int count=0;>>>> std::cout<<"main: Entry"<<std::endl;>>>> IClassFactory *pCf;>> IUnknown *pUnk;>> IMyServer *pMyServer;>> HRESULT hr;>>>>>> std::cout<<"main: calling CoInitialize() \n"<<std::endl;>>>> hr=CoInitialize(NULL);>> if(FAILED(hr))>> {>> std::cout<<"main: CoInitialize Failed!\n"<<std::endl;>> exit(-1);>> }>>>> std::cout<<"main: CoInitialize OK\n"<<std::endl;>> std::cout<<"main: Calling CoGetClassObject\n"<<std::endl;>>>>hr=CoGetClassObject(CLSID_MyServer,CLSCTX_INPROC_SERVER,NULL,IID_IClassFactory,(void**)&pCf);>> if(FAILED(hr))>> {>> std::cout<<"main: CoGetClassObject Failed!\n"<<std::endl;>> goto EXIT00;>> }>>>> std::cout<<"main: CoGetClassObject OK\n"<<std::endl;>> std::cout<<"main: callingpCf->CreateInstance(NULL,IID_IUnknown,...)"<<std::endl;>>>> hr=pCf->CreateInstance(NULL,IID_IUnknown,(void**) &pUnk);>> if(FAILED(hr))>> {>> std::cout<<"main: pCf->CreateInstance(NULL,IID_IUnknown,...)Failed!\n"<<std::endl;>> goto CLEANUP00;>> }>>>> std::cout<<"main: pCf->CreateInstance(NULL,IID_IUnknown,...)OK"<<std::endl;>>>> std::cout<<"main: callingpUnk->QueryInterface(IID_IMyServer,...)"<<std::endl;>> hr=pUnk->QueryInterface(IID_IMyServer,(void**) &pMyServer);>> if(FAILED(hr))>> {>> std::cout<<"main: pUnk->QueryInterface(IID_IMyServer,...)Failed!\n"<<std::endl;>> goto CLEANUP01;>> }>>>> std::cout<<"main: pUnk->QueryInterface(IID_IMyServer,...)OK\n"<<std::endl;>>>> std::cout<<"main: Now Calling into the IMyServerInterface\n"<<std::endl;>>>> hr=pMyServer->Visible(VARIANT_TRUE);>> if(FAILED(hr))>> {>> std::cout<<"main: pMyServer->Visible()Failed!\n"<<std::endl;>> goto CLEANUP02;>> }>>>>>> hr=pMyServer->Animate(VARIANT_TRUE,200);>> if(FAILED(hr))>> {>> std::cout<<"main: pMyServer->Animate()Failed!\n"<<std::endl;>> goto CLEANUP02;>> }>>>> std::cout<<"main: pMyServer->Animate() OK!\n"<<std::endl;>>>> MSG msg;>>>> while(!bDone)>> {>>>> GetMessage(&msg, NULL, 0, 0);>>>> if ( msg.message==WM_KEYUP )>> {>> int nVirtKey = (int) msg.wParam;>> // if the user pressed the ESCAPE key, then>> // print the text the user entered and quit>> if ( nVirtKey==VK_ESCAPE )>> {>>>> DestroyWindow(hWnd);>> bDone = true;>> break;>> }>> }>>>> // process message>> TranslateMessage(&msg);>> DispatchMessage(&msg);>> }>>>> CLEANUP02:>> std::cout<<"main: calling IMyServer::Release"<<std::endl;>> if(pMyServer){>> pMyServer->Release();>> pMyServer = NULL;>> }>>>> CLEANUP01:>> std::cout<<"main: calling IUnknown::Release"<<std::endl;>> if(pUnk){>> pUnk->Release();>> pUnk = NULL;>> }>>>>>> CLEANUP00:>> std::cout<<"main: calling IClassFactory::Release"<<std::endl;>> if(pCf){>> pCf->Release();>> pCf = NULL;>> }>>>> EXIT00:>> CoUninitialize();>> std::cout<<"main: We are done!"<<std::endl;>>>>>> ReleaseMutex(hMutex);>>>> }>>>>>> int main(int argc, char* argv[])>> {>> HANDLE handle;>> HANDLE hMutex;>> unsigned uUnUsedThreadId;>>>>>> hMutex = CreateMutex(NULL,FALSE,NULL);>>>> if(hMutex==NULL)>> {>> printf("Primary Thread - error callingCreateMutex().\n");>> exit(0xFFFFFFFF);>> }>>>> // create a new thread to allow user input>>>> handle = (HANDLE) _beginthreadex(NULL,0,InputThreadProc,(void*) hMutex, 0, &uUnUsedThreadId);>>>> if( (int) handle==-1)>> {>> printf("Failed to create thread");>> return 0;>> }>> // wait for the new thread to finish>>>> handle = (HANDLE) WaitForSingleObject(handle,INFINITE);>>>>>> return 0;>> }>>>>

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