Should there be a difference between an empty BSTR and a NULL BSTR?

Question

When maintaining a COM interface should an empty BSTR be treated the same way as NULL? In other words should these two function calls

Answer 1

The easiest way to handle this dilemma is to use CComBSTR and check for .Length() to be zero. That works for both empty and NULL values.

However, keep in mind, empty BSTR must be released or there will be a memory leak. I saw some of those recently in other's code. Quite hard to find, if you are not looking carefully.