[vtkusers] Universal Binary of vtk on Mac OS X... initial investigations...

[Sean McBride]

Hi all,

I've been looking at getting cmake and vtk to build as Universal
Binaries on Mac OS X.  (A Universal Binary is a _single_ executable file
that has both PowerPC and Intel object code, and so runs natively on
both types of Mac).

Building something as universal is pretty easy, at least in the sense
that it only takes a few parameters to gcc.  It's hard in the sense that
you must be sure you write your code in a portable way.

Now obviously vtk is very portable, but I worry about something: when I
build vtk, I see output like this:

-- Check size of int
-- Check size of int - done
-- Check if the system is big endian
-- Check if the system is big endian - big endian

The size of int and endianess of the _build computer_ is unimportant. 
My build computer may be big endian, but if I'm building as universal
then I'm building for both big and little cpus.

Does vtk actually use this information?  That is, does it assume that
the build computer is of the same architecture I am building _for_?

Thanks!

-- 
____________________________________________________________
Sean McBride, B. Eng                 sean at rogue-research.com
Rogue Research                        www.rogue-research.com 
Mac Software Developer              Montréal, Québec, Canada