[Insight-developers] Explicit instantiation linking issues on mac platform

[Hans Johnson]

Julien,

The problems occur in compiling the Testing and Examples directories under
ITK. 

Hans


On 9/6/06 4:55 PM, "Julien Jomier" <julien.jomier at kitware.com> wrote:

> Hans,
> 
> Do you get the error when compiling ITK or an external program using ITK?
> 
> Julien
> 
> Hans Johnson wrote:
>> Zach,
>> 
>> I should have been more explicit earlier, but I am building statically, and
>> the errors are occuring at link time rather than at run time.  The manual
>> fix is to re-arrange the library link order to put -lITKCommonExplicit
>> before -lITKCommon.  When I get back to that machine, I'll give a concrete
>> example.
>> 
>> The errors are of the "symbol not found" link error, and the symbols are
>> ones needed by ITKCommonExplicit and found in ITKCommon.
>> 
>> Thanks,
>> Hans
>> 
>> 
>> 
>> On 9/6/06 4:38 PM, "Zachary Pincus" <zpincus at stanford.edu> wrote:
>> 
>>> I think that the TARGET_LINK_LIBRARIES statement is trying to link
>>> ITKCommonExplicit into the ITKCommon library, so that an app can just
>>> link to the common lib and the explicit one will be pulled in.
>>> 
>>> Is that not working? What are the link errors you see when building
>>> applications?
>>> 
>>> You can check what libraries are linked to an object file (executable
>>> or other library) on OS X with 'otool -L'. It would be worth checking
>>> what's linked to libITKCommon.dylib, and in what order.
>>> 
>>> Zach
>>> 
>>> On Sep 6, 2006, at 8:20 AM, Hans Johnson wrote:
>>> 
>>>> Hello Fellow Developers!
>>>> 
>>>> I wanted to alert the group to a small issue with linking on mac
>>>> platform
>>>> with explicit instantiation, and get some advice on how to fix the
>>>> problem.
>>>> 
>>>> The issue is that when explicit instantiation is used the extra
>>>> ITKCommonExplicit library needs to be linked into the applications
>>>> along
>>>> with ITKCommon library.  The file  Insight/Code/Common/
>>>> CMakeLists.txt  code
>>>> has the following
>>>> 
>>>> IF(ITK_EXPLICIT_INSTANTIATION)
>>>>   TARGET_LINK_LIBRARIES (ITKCommon ITKCommonExplicit)
>>>> ENDIF(ITK_EXPLICIT_INSTANTIATION)
>>>> 
>>>> Which I interpret as "ITKCommon depends upon ITKCommonExplicit, so
>>>> whenever
>>>> you use -lITKCommon then also follow with -lITKCommonExplicit
>>>> during linking
>>>> stages".  The problem is that the linking dependancies are
>>>> backwards, and
>>>> that ITKCommonExplicit needs to preceed ITKCommon.
>>>> 
>>>> What needs to happen is that somehow ITKCommonExplicit needs to be
>>>> prepended
>>>> to many of the linking stages.
>>>> 
>>>> I would like some guidance on resolving this issues, because the
>>>> "easy way"
>>>> touches quite a lot of CmakeLists.txt files and adds complexity to
>>>> linking
>>>> logic.
>>>> 
>>>> 
>>>> Regards,
>>>> Hans
>>>> 
>>>> Food For Thought---Another less intrusive way to do this would be
>>>> to have
>>>> conditionals in the Insight/Code/Common/CMakeLists.txt file that
>>>> builds the
>>>> explicit instantiations right into the ITKCommon library rather
>>>> than having
>>>> a separate library.  This will make life a lot easier as the number
>>>> and
>>>> names of the library linking would be constant across configuration
>>>> options.
>>>> 
>>>> 
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>>>> Insight-developers at itk.org
>>>> http://www.itk.org/mailman/listinfo/insight-developers
>> 
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