From: Howard Hinnant (hinnant_at_[hidden])
Date: 2000-01-20 10:41:44
>> However: for compressed pair do we need is_empty at all? If either of
>the
>> template parameters are a class, then why not derive from them regardless?
>> It can't do any harm and it may just do some good.
>
>No, we do not need is_empty for compressed_pair. Your logic is correct.
One potential advantage of using is_empty instead of is_class is that
swap can explicitly optimize away the swap call for the empty member if
is_empty is used. The compiler may do this as well, depending upon the
quality of the compiler.
-Howard