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Hi, I seen some memory leak in my code during analyzing using DevPartner tool. I tried to fix it but didnt get any success. Please help me here. Description: I am having an array of ATL::CString cla

Hi,

I seen some memory leak in my code during analyzing using DevPartner tool. I tried to fix it but didnt get any success. Please help me here.

Description: I am having an array of ATL::CString class. In loop i am converting these strings to _variant_t type like:

_variant_t varValue = LPCTSTR(m_StrArray[i]);

Then i am having one COM API: AddKey(VARIANT *pVarVal); Which takes VARIANT* as an input parameter.

I am calling this API by passing varValue as a paremeter in the following way:
spSomeInterface->AddKey(&varValue);

This API internally assign its parameter to _variant_t variable like:

HRESULT AddKey(VARIANT *pVarVal)
{
m_vardata.Attach(*pVarVal);
}

When i run this code then DevPartner tool shows memory leak in the following line:
_variant_t varValue = LPCTSTR(m_StrArray[i]);

Please assist me to fix this leak. Its very important to fix because this leak exist in my core component.

suppose m_StrArray is the array of CString objects.
 
for(int i = 0; i < m_StrArray.Count(); i++)
{
    _variant_t varValue = LPCTSTR(m_StrArray[i]); //HERE IS MEMORY LEAK
     m_spSomeInterface->AddKey(&varValue);
}
 
AddKey function is defined as:
 
STDMETHODIMP CMyClass::AddKey(VARIANT *pVarVal)
{
    TItemMap::iterator it = m_Map.insert(_variant_t(), true).first;
    it->first.Attach(*pVarVal);    
}
 
Where m_Map is the map of _variant_t and bool value. Its member variable. So i am first creating a place holder for variant and then i am attaching it with the input VARIANT* parameter.

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harish_dixit1

ASKER

Sorry these two questions are same but first i submitted to MS Dev zone and i didnt get any response so i thought zone is not correct thats why i posted it in other zone also.

harish_dixit1

ASKER

Thanks for reply.

I tried it as you suggested, but problem still exist.

I am giving stack trace shown by DevPartner tool here.
I am getting memory leak in the following function in comutil.h header file:

inline _variant_t& _variant_t::operator=(const wchar_t* pSrc)
{
_COM_ASSERT(V_VT(this) != VT_BSTR || pSrc == NULL || V_BSTR(this) != pSrc);

// Clear the VARIANT (This will SysFreeString() any previous occupant)
//
Clear();

V_VT(this) = VT_BSTR;

if (pSrc == NULL) {
V_BSTR(this) = NULL;
}
else {
V_BSTR(this) = ::SysAllocString(pSrc);

if (V_BSTR(this) == NULL) {
_com_issue_error(E_OUTOFMEMORY);
}
}

return *this;
}

And Tool shows the leak in my code:
for(int i = 0; i < m_StrArray.Count(); i++)
{
_variant_t varValue = LPCTSTR(m_StrArray[i]); //HERE IS MEMORY LEAK
m_spSomeInterface->AddKey(&varValue);
}

If u want some more info then i can provide it.
Thanks.

harish_dixit1

ASKER

I tried to comment the call of API m_spSomeInterface->AddKey(&varValue);
in the loop then DevPartner doesn't show any memory leak. It means the problem is not in the statement where we are converting String to variant. But i think problem is due to API call m_spSomeInterface->AddKey(&varValue);. Because this API is doing following assignment internally:

it->first.Attach(*pVarVal);

So its attaching param VARIANT* to _variant_t (it->first is of type _variant_t).

harish_dixit1

ASKER

I have attached 2 files. One header file where map data structure is defined and source file where i am accessing the interface method.

I am using smart pointer for interface so no need to call Release on interface pointer.
Source.txt
Header.txt