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

[Neil Weisenfeld]

I don't see the itksys version in my checkout (there is no itksys 
directory),  however the current dynamic loader is both trivial in 
implementation and works -- why change it?  All that needs to happen is 
that the special __APPLE__ case needs to be *skipped* for the proper 
machines in favor of the vanilla Unix implementation.

Here's the open question: is the problem all Macs with recent OS's or 
just Intel ones.  Was the problem you experienced on a PowerPC machine 
running a recent MacOS?

Since Intel Macs *have* to have a recent OS, the solution of changing 
#if defined(__APPLE__)
to
#if defined(__APPLE__) && !defined(__i386__)
will fix the problem for, at least, Intel machines and will not break 
non-Intel machines.


Neil




Stefan Klein wrote:
> Hi Neil,
> 
> I found the same bug (or actually, somebody else, who compiled my code 
> on a mac).
> 
> In the itksys directory (<your-itk-binary-dir>\Utilities\itksys) you can 
> find another DynamicLoader, which is more up-to-date and works well on 
> new Apples (and also on old ones i guess). Its interface is almost the 
> same, and you can include it with the following statement:
> 
> #include <itksys/DynamicLoader.hxx>
> 
> the class 'lives' in the itksys namespace by the way.
> 
> Question to the ITK-gurus: Why does the itk::DynamicLoader not use the 
> itksys::DynamicLoader internally?
> 
> Regards,
> Stefan.
> 
> 
> 
> At 15:34 20/07/06, Neil Weisenfeld wrote:
>> 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
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> 
>