[boost] Re: Empty member optimization

From: David B. Held (dheld_at_[hidden])
Date: 2004-09-11 10:50:11

Joao Abecasis wrote:
> [...]
> I took a look at Borland 5.5.1 and was able to come up with a few tricks 
> that provide some form of EBO. But it's a no win situation because there 
> is no way to actually determine it a given type is empty (with this 
> compiler) to start with. For instance, empty classes take up the size of 
> the base class. If the (final) base class is empty it's size is 8 but if 
> it has a single char data member it's size will be 1!

You need to set structure packing, probably.  Something like this:

#include <pshpack1.hpp>

// Your code here

#include <poppack1.hpp>

Also set alignment for WORD boundaries rather than DWORD.

Dave