[boost] Re: Determining padding

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