C++ Application That Uses MSI Automation API 32 and 64bit - c++

Question

I am trying to create simple c++ win32 console app(in vs2010) that calls windows installer automation api. But I am failing so far. This approach causes the "Microsoft C++ exception: _com_error at memory location" error.
How to correctly use this api? How to make it work correctly on 32 and 64 bit system with only one .exe file?
Many thanks,
Marek
#include "stdafx.h"
#include <windows.h>
#include <atlstr.h>
#import "msi.dll"
using namespace WindowsInstaller;
_bstr_t GetInstalledProduct(InstallerPtr pInstaller,_bstr_t upgradeCode){
StringListPtr installedProducts = pInstaller->GetRelatedProducts(upgradeCode);
return installedProducts->Count > 0 ? installedProducts->GetItem(0) : "";
}
int _tmain(int argc, _TCHAR* argv[])
{
::CoInitialize(NULL);
InstallerPtr pInstaller("WindowsInstaller.Installer");
_bstr_t upgradeCode("4C34BD16-CAD4-4059-B074-777793406C5F");
_bstr_t installedProduct = GetInstalledProduct(pInstaller, upgradeCode);
StringListPtr features = pInstaller->GetFeatures(installedProduct);
::CoUninitialize();
return 0;
}

Answer 1

I finally found the solution. The correct way is include msi.lib in linker includes and use Msi.h from windows sdk.
#include "stdafx.h"
#include <windows.h>
#include <Msi.h>
int _tmain(int argc, _TCHAR* argv[])
{
wchar_t productCode[255];
int result = MsiEnumRelatedProducts(L"{4C34BD16-CAD4-4059-A074-777493406C5F}", 0, 0, productCode);
wchar_t featureName[255];
wchar_t featureParent[255];
MsiEnumFeatures(productCode, 0, featureName, featureParent);
INSTALLSTATE featureState = MsiQueryFeatureState(productCode, L"FeatureName");
return 0;
}