// имеем map
   map <string, string> m_mapKey2Category;

   ...
  
   // получаем две строки в виде _bstr_t
   _bstr_t sCategory=GetKey(pCategory);
   _bstr_t bsKey=ItemName(atr);

   // засовываем их в map
   m_mapKey2Category[string(bsKey)]=string(sCategory);

   ...

   // потом освобождаем
   m_mapKey2Category.clear();

Detected memory leaks!
Dumping objects ->
{2419} normal block at 0x06EBD318, 48 bytes long.
Data: <f33a788d-d9f3-42> 66 33 33 61 37 38 38 64 2D 64 39 66 33 2D 34 32
{2418} normal block at 0x06EBD290, 72 bytes long.
Data: < r 8M r > D8 72 01 01 38 4D EB 06 D8 72 01 01 CD CD CD CD
{2413} normal block at 0x06EBD220, 48 bytes long.
Data: <de7c1087-6b38-4c> 64 65 37 63 31 30 38 37 2D 36 62 33 38 2D 34 63
{2412} normal block at 0x06EBD198, 72 bytes long.
Data: < r p r > D8 72 01 01 70 96 EB 06 D8 72 01 01 CD CD CD CD

И так далее...

   m_mapKey2Category[string("123")]=string("Bla-bla-bla");

//Update static text with new value
BSTR tmpBStr;

m_pObject1->get_ObjectString(&tmpBStr);
_bstr_t tmpbstr(tmpBStr, FALSE); //necessary to avoid a memory leak

SetDlgItemText(IDC_CURPROPVAL, tmpbstr);

Note The conversion issue does not apply in a Unicode build. However, conversion is needed in a Win32 build.

In addition to the casting issue, there is also a memory issue. If the following code sample had been used, instead of the preceding code, a memory leak would have resulted:

//Update static text with new value
BSTR tmpBStr;

m_pObject1->get_ObjectString(&tmpBStr);
_bstr_t tmpbstr;

tmpbstr= tmpBStr; //Caution: Memory leak occurs
SetDlgItemText(IDC_CURPROPVAL, tmpbstr);

The leak occurs when the tmpbstr variable is initialized. A call to SysAllocString (reference available in the Component Services section of the Platform SDK) is automatically made when creating the tmpbstr variable. This new allocation is never freed later, resulting in a memory leak. Using this version of the _bstr_t constructor avoids the issue by attaching the BSTR object to tmpbstr without a call to SysAllocString. For more information on this issue, see _bstr_t::_bstr_t (reference available in the C++ Language Reference section of the Visual C++ Documentation).

for (...)
{
   _bstr_t sCategory=GetKey(pCategory);
   _bstr_t bsKey=ItemName(atr);

   m_mapKey2Category[string(bsKey)]=string(sCategory); // Вот так утечки будут

   m_mapKey2Category[string("123")]=string("Bla-bla-bla"); // А вот так нет
}

for (...)
{
   _bstr_t sCategory=GetKey(pCategory);
   _bstr_t bsKey=ItemName(atr);

   m_mapKey2Category[ string(bsKey) ]=string(sCategory); // Вот так утечки будут

   m_mapKey2Category[string("123")]=string("Bla-bla-bla"); // А вот так нет
}

for (...)
{
   _bstr_t sCategory=GetKey(pCategory);
   _bstr_t bsKey=ItemName(atr);

   m_mapKey2Category[string(bsKey)]=string(sCategory);

   SysFreeString(sCategory);
   SysFreeString(bsKey);
}

inline _variant_t GetKey ( IAttributesPtr a )
{
  _variant_t key;
  a->get_Key ( &key );
  return key;
}

inline _variant_t ItemName ( IAttributeItemPtr a )
{
  _variant_t key;
  a->get_Key ( &key );
  return key;
}

В>for (...)
В>{
В>   _bstr_t sCategory=GetKey(pCategory);
В>   _bstr_t bsKey=ItemName(atr);

В>   m_mapKey2Category[ string(bsKey) ]=string(sCategory); // Вот так утечки будут

В>   m_mapKey2Category[string("123")]=string("Bla-bla-bla"); // А вот так нет
В>}
В>

volatile const char* str1 = bsKey;
volatile const char* str2 = sCategory;