Understanding The COM Single-Threaded Apartment Part 1

#define _WIN32_WINNT 0x0400

#include <windows.h>
#include <stdio.h>

#import "..\..\..\..\LegacyCOMObject1\Debug\LegacyCOMObject1.dll"
using namespace LEGACYCOMOBJECT1Lib;





// Simple function that displays the current thread ID.
void DisplayCurrentThreadId()
{
  TCHAR szMessage[256];

  sprintf (szMessage, "Thread ID : 0x%X", GetCurrentThreadId());

  ::MessageBox(NULL, szMessage, "TestMethod1()", MB_OK);
}





int main()
{
  ::CoInitializeEx(NULL, COINIT_APARTMENTTHREADED);
  //::CoInitializeEx(NULL, COINIT_MULTITHREADED);

  DisplayCurrentThreadId();

  if (1)
  {
    ILegacyCOMObject1Ptr spILegacyCOMObject1;

    spILegacyCOMObject1.CreateInstance(__uuidof(LegacyCOMObject1));

	spILegacyCOMObject1 -> TestMethod1();
  }

  ::CoUninitialize();

  return 0;
}