Given:
{
CComSafeArray<VARIANT> sa;
CComVariant ccv(L"test");
sa.Add(ccv, TRUE);
}
I was hoping the dtor of CComSafeArray would call ::VariantClear on each contained member and the documentation seems to indicate that:
In certain cases, it may be preferable to clear a variant in code without calling VariantClear. For example, you can change the type of a VT_I4 variant to another type without calling this function. Safearrays of BSTR will have SysFreeString called on each element not VariantClear. However, you must call VariantClear if a VT_type is received but cannot be handled. Safearrays of variant will also have VariantClear called on each member.
(source: http://msdn.microsoft.com/en-us/library/windows/desktop/ms221165(v=vs.85).aspx)
But I see no such thing happening in the code in atlsafe.h.
Am I just looking in the wrong place or is this just supposed to happen as a side-effect of ::SafeArrayDestroy() -- which is the only thing happening via the CComSafeArray dtor.
Ultimately VariantClear
will get called on the contents of the CComSafeArray object, albeit after progressing through multiple layers. CComSafeArray::~CComSafeArray()
calls CComSafeArray::Destroy()
which is ultimately a wrapper of SafeArrayDestroy()
:
HRESULT Destroy()
{
HRESULT hRes = S_OK;
if (m_psa != NULL)
{
hRes = Unlock();
if (SUCCEEDED(hRes))
{
hRes = SafeArrayDestroy(m_psa);
if (SUCCEEDED(hRes))
m_psa = NULL;
}
}
return hRes;
}
SafeArrayDestroy()
is documented as calling VariantClear
on its contents if it contains VARIANTs:
Safe arrays of variant will have the VariantClear function called on each member and safe arrays of BSTR will have the SysFreeString function called on each element.