[Insight-developers] I/O factory loading needs to be updated for Intel Macs/Mac OS 10.4 (easy fix)

[Neil Weisenfeld]

I'm a fairly new Mac owner and am relying on a custom I/O factory that 
I've written for ITK.

Currently, builds on my Intel-based MacBook Pro (OS/X 10.4.7) cause a 
bus error when trying to load my custom module (but keep reading).

The ITK dynamic loading stuff in Code/Common/itkDynamicLoader.cxx has a 
special case for #ifdef __APPLE_.  This makes use of deprecated 
functions in order to perform dynamic module loading.  Simply disabling 
this special __APPLE__ case on my builds allows the normal Unix (dlopen, 
etc.) code path to be compiled in and this works correctly.

If this only applies to the Intel Macs, then a quick fix is to change

#if defined( __APPLE__ )
to
#if defined(__APPLE__) && !defined(__i386__)

should do the trick, however this Apple tech note seems to indicate that 
the method in use is simply deprecated (Apple says "discouraged"):

http://developer.apple.com/documentation/DeveloperTools/Reference/MachOReference/Reference/reference.html

It would be nice if this were fixed in the official release for me and 
the slicer branch as this breaks Slicer, too.  I guess I'm one of a 
small number of people who are using loadable I/O factories.  I'm not 
sure what the best fix is: are there still people running ITK on 
platforms that require the older NSLinkModule stuff, etc?  Maybe we can 
hear from some Mac experts in the audience.


Regards,
Neil