Re: compilation error when using CComPtr w/ CUnknown-derived objects

Actually, adding "public IUnknown" to the class declaration only fixed the
compilation issue but I am now having a problem when the object is
instantiated.

When CComPtr is on the same line (see Example 1 below) the object is correct
but when the CComPtr is outside of the function (see Example 2 below) , the
object is corrupted. Any idea what's wrong now? Thank you. No?l

// Sample class

class CTest :
 public CUnknown, public IUnknown
{
public:
 DECLARE_IUNKNOWN

 CTest(void) :
  CUnknown(_T("CTest"), NULL)
 {
  a = 5;
  b = 7;
 }

 CTest(LPUNKNOWN pUnk, HRESULT* phr) :
  CUnknown(_T("CTest"), pUnk, phr)
    {
  a = 3;
  b = 6;
 }

 static CUnknown* WINAPI CreateInstance(LPUNKNOWN punk, HRESULT *phr)
 {
  ASSERT(phr);

  CTest *pNewObject = new CTest(punk, phr);
  if (pNewObject == NULL) {
   if (phr)
    *phr = E_OUTOFMEMORY;
  }

  return pNewObject;
 }

 BOOL Hello()
 {
  return TRUE;
 }

protected:
 int a, b;
};

// Example 1: created object is OK

void Instantiate(void)
{
 HRESULT hr = S_OK;
 CComPtr<CTest> pTest = reinterpret_cast<CTest*>(CTest::CreateInstance(NULL,
&hr));
}

Debugger output:

- pTest {0x003e5e50} ATL::CComPtr<CTest>
- ATL::CComPtrBase<CTest> {p=0x003e5e50 } ATL::CComPtrBase<CTest>
- p 0x003e5e50 {a=0x00000003 b=0x00000006 } CTest *
+ CUnknown {m_pUnknown=0x003e5e50 m_cRef=0x00000001 } CUnknown
+ IUnknown {...} IUnknown
  a 0x00000003 int
  b 0x00000006 int

// Example 2: created object is corrupted

CComPtr<CTest> pTest;

void Instantiate(void)
{
 HRESULT hr = S_OK;
 pTest = reinterpret_cast<CTest*>(CTest::CreateInstance(NULL, &hr));
}

Debugger output:

- pTest {0x003e5f08} ATL::CComPtr<CTest>
- ATL::CComPtrBase<CTest> {p=0x003e5f08 } ATL::CComPtrBase<CTest>
- p 0x003e5f08 {a=0xabababab b=0x00000000 } CTest *
+ CUnknown {m_pUnknown=0x00000006 m_cRef=0xfdfdfdfd } CUnknown
+ IUnknown {...} IUnknown
  a 0xabababab int
  b 0x00000000 int

--
No?l
http://noeld.com/