Question

I have the following code in C++. Do I need to free ‘varDest’ variable?

VARIANT val;
if(SUCCEEDED(classObj->Get(pwPropName, 0, &val, NULL, 0)))  //WMI property retrieval
{
    //Then at some point
    VARIANT varDest;
    varDest.vt = VT_EMPTY;
    if(SUCCEEDED(::VariantChangeType(&varDest, 
        const_cast<VARIANT *>(&val), 0, VT_BSTR)))
    {
        //Do I need to call the following?
        VariantClear(&varDest);
    }

    VariantClear(&val);
}

Answer 1

Yes you must call VariantClear. The VariantChangeType method if successful will essentially coerce a copy of the source into the destination. This copy in the destination is now independently tracked and must be independently cleared.