C++ COM Code Example: Opening a Queue to Read Messages (Windows CE 5.0)

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The following code example opens a known public queue (creating a new queue if the queue is not found) with receive access.

// main.cpp
//
// sample program for the MSMQ COM usage
#include "stdafx.h"
//
// MSMQ COM sample using smart pointer
//
// following sample code receives a message in a private queue named "Q1"
//
#include <atlbase.h>
#include <mqoai.h>
// mqoa.lib should be included to the projet
// mqoa.lib is under Public\SERVERS\OAK\LIB\X86\RETAIL
//#import "mqoa.dll" no_namespace   // not supported
HRESULT OpenAndReadQ1()
{
   CComQIPtr<IMSMQQueueInfo, &IID_IMSMQQueueInfo> ipQueueInfo;
   HRESULT hr = S_OK;
// hr = ipQueueInfo.CoCreateInstance(CLSID_MSMQQueueInfo);  // this form is not supported
   hr = CoCreateInstance(
         CLSID_MSMQQueueInfo,
         NULL,
         CLSCTX_SERVER,
         IID_IMSMQQueueInfo,
         (void**)(&ipQueueInfo.p));
   if(hr != S_OK)
      return hr;
   hr = ipQueueInfo->put_PathName(L".\\private$\\Q1");
   if(hr != S_OK)
      return hr;
   CComQIPtr<IMSMQQueue, &IID_IMSMQQueue> ipReceiveQueue;
   hr = ipQueueInfo->Open(MQ_RECEIVE_ACCESS, MQ_DENY_NONE, &ipReceiveQueue);
   if(hr != S_OK)
   {
      printf("queue open error\r\n");
      return hr;
   }
   printf("queue opened\r\n");
   CComQIPtr<IMSMQMessage, &IID_IMSMQMessage> ipMessage;
   VARIANT vtFalse;
   VariantInit(&vtFalse);
   vtFalse.vt = VT_BOOL;
   vtFalse.boolVal = FALSE;
   
   VARIANT vtTrue;
   VariantInit(&vtTrue);
   vtFalse.vt = VT_BOOL;
   vtFalse.boolVal = TRUE;
   VARIANT vtReceiveTimeout;
   VariantInit(&vtReceiveTimeout);
   vtReceiveTimeout.lVal = ((long)1000);        // 1 second receive timeout.
   vtReceiveTimeout.vt = VT_I4;
   hr = ipReceiveQueue->Receive(&vtFalse, &vtTrue, &vtTrue, &vtReceiveTimeout, &ipMessage);
   if(hr != S_OK)   // if errornous end
   {
      ipReceiveQueue->Close();
      if(hr == MQ_ERROR_IO_TIMEOUT)
         printf("time out\r\n");
      else
         printf("received error 0x%0X\r\n", hr);
      return hr;
   }
   VARIANT vtText;
   VariantInit(&vtText);
   hr = ipMessage->get_Body(&vtText);
   if(hr != S_OK)
   {
      ipReceiveQueue->Close();
      return -1;
   }
   wprintf(L"received: %s\r\n", vtText.bstrVal);
   SysFreeString(vtText.bstrVal);
   ipReceiveQueue->Close();
   return hr;
}
int WINAPI WinMain(   HINSTANCE hInstance,
               HINSTANCE hPrevInstance,
               LPTSTR    lpCmdLine,
               int       nCmdShow)
{
   printf("MSMQ COM sample\r\n");

   HRESULT hr = CoInitializeEx(NULL, COINIT_MULTITHREADED);
   if(hr == S_OK)
   {
      OpenAndReadQ1();
      CoUninitialize();
   }

   return 0;
}

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C++ COM Code Example: Opening a Queue to Read Messages (Windows CE 5.0)

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