On Wed, Oct 1, 2008 at 9:23 AM, Andrey Semashev <andrey.semashev@gmail.com> wrote:
Emil Dotchevski wrote:
I need to allocate an object of type T, but I also need to bundle it in a single memory allocation with an object of class U. Something like "new std::pair<T,U>" would work, except that U is a rather heavy type and I want to pimpl it away into a cpp.
This means that the cpp needs to deal with the alignment of T and U when allocating the memory. For that purpose, I could use type_traits/type_with_alignment.hpp in my header, but when I looked at it, I was blown away by how much crap it includes (remember, I want my header to be very very light.)
Sorry if I'm missing something, but why would you need to include these headers in your header? Just forward-declare your internal pimpl class and define it in cpp. It is cpp where you would include type_with_alignment.hpp & co. and this is not that critical, is it?
The problem is that I still need the bootstrap code to be in the header, it's a function template with a single parameter T. The header needs to tell the cpp what's the size and alignment for T, and also pass pointers to a function that can copy a T and a function that destroys it. The cpp then can allocate the memory block, init the U object and copy the T. So, at least I need to include alignment_of.hpp which is so heavy it practically nullifies my efforts to pimpl the U type away in the cpp. Emil Dotchevski Reverge Studios, Inc. http://www.revergestudios.com/reblog/index.php?n=ReCode