[Insight-users] undefined reference Templated Class

Thu Sep 6 12:25:37 EDT 2007

Hey Mark,

(thanks, should've paid attention when Bram was giving colleges:)

Ive gotten rid of the shadows error by using #ifndef 
but now I still get an error (see below). Probably something
to do with the templates cause it works without  templates.
Error:
C:\Insight\myPrograms\generateProblems\gradient.cxx:22: error: expected constructor, destructor, or
type conversion before '<' token
C:\Insight\myPrograms\generateProblems\gradient.cxx:22: error: expected `;' before '<' token
C:\Insight\myPrograms\generateProblems\gradient.cxx:52: error: expected init-declarator before '<' t
oken
C:\Insight\myPrograms\generateProblems\gradient.cxx:52: error: expected `;' before '<' token
C:\Insight\myPrograms\generateProblems\gradient.cxx:71: error: expected init-declarator before '<' t
oken
C:\Insight\myPrograms\generateProblems\gradient.cxx:71: error: expected `;' before '<' token
C:\Insight\myPrograms\generateProblems\gradient.cxx:89: error: expected init-declarator before '<' t
oken
C:\Insight\myPrograms\generateProblems\gradient.cxx:89: error: expected `;' before '<' token
mingw32-make[2]: *** [CMakeFiles/generateProblems.dir/gradient.obj] Error 1
mingw32-make[1]: *** [CMakeFiles/generateProblems.dir/all] Error 2
mingw32-make: *** [all] Error 2

----- Original Message ----
From: Mark Bouts <mark at invivonmr.uu.nl>
To: Lars Nygard <lnygard at yahoo.com>
Sent: Thursday, September 6, 2007 8:55:38 AM
Subject: Re: [Insight-users] undefined reference Templated Class

Hi Lars,

make sure that you don't use a double declaration. This means that you 
must be carefull including both *.h and *.cpp files. Please do make sure 
you have include-guards in your *.h file.
Ie.

#ifndef GRADIENT_H
#define GRADIENT_H

/** your code */

#endif /* GRADIENT_H*/

Additionally make sure you don't declare the class gradient in both the 
*.cpp and *.h files.

Hope it helps!

Grtz,

Mark

On Thu, 6 Sep 2007, Lars Nygard wrote:

> Hi Gaetan,
>
>
>
> Thanks for the help. Ive tried that but than I get the following
> error:
>
> In file included from C:\Insight\myPrograms\generateProblems\/gradient.h:98,
>                 from C:\Insight\myPrograms\generateProblems\/main.h:18,
>                 from C:\Insight\myPrograms\generateProblems\main.cxx:13:
> C:\Insight\myPrograms\generateProblems\/gradient.cxx:18: error: declaration of `class
> C:\Insight\myPrograms\generateProblems\/gradient.h:20: error:  shadows template parm
> C:\Insight\myPrograms\generateProblems\/gradient.cxx:20: error: cannot declare member
> ient<TImage>::gradient' within `gradient<TImage>'
> C:\Insight\myPrograms\generateProblems\/gradient.cxx:47: error: declaration of `class
> C:\Insight\myPrograms\generateProblems\/gradient.h:20: error:  shadows template parm
> C:\Insight\myPrograms\generateProblems\/gradient.cxx:51: error: cannot declare member
> ient<TImage>::LoadImageA' within `gradient<TImage>'
> C:\Insight\myPrograms\generateProblems\/gradient.cxx:66: error: declaration of `class
> C:\Insight\myPrograms\generateProblems\/gradient.h:20: error:  shadows template parm
> C:\Insight\myPrograms\generateProblems\/gradient.cxx:70: error: cannot declare member
> ient<TImage>::SaveImage' within `gradient<TImage>'
> C:\Insight\myPrograms\generateProblems\/gradient.cxx:84: error: declaration of `class
> C:\Insight\myPrograms\generateProblems\/gradient.h:20: error:  shadows template parm
> C:\Insight\myPrograms\generateProblems\/gradient.cxx:88: error: cannot declare member
> ient<TImage>::CompGradient' within `gradient<TImage>'
> mingw32-make[2]: *** [CMakeFiles/generateProblems.dir/main.obj] Error 1
> mingw32-make[1]: *** [CMakeFiles/generateProblems.dir/all] Error 2
> mingw32-make: *** [all] Error 2
> ----- Original Message ----
> From: Gaëtan Lehmann <gaetan.lehmann at jouy.inra.fr>
> To: Lars Nygard <lnygard at yahoo.com>
> Cc: insight-users at itk.org
> Sent: Thursday, September 6, 2007 7:37:04 AM
> Subject: Re: [Insight-users] undefined reference Templated Class
>
>
> Hi Lars,
>
> Your gradient class is templated, so you have to include the cxx file
> at the end of the header to make it work.
>
> #include "gradient.cxx"
>
> Because of the template, you can't (easily) build the code in
> your .cxx file and put it in a shared object.
>
> Regards,
>
> Gaëtan
>
>
>
>
> Le 6 sept. 07 à 16:28, Lars Nygard a écrit :
>
>> hi everybody,
>>
>> Id really appreciate some help with this. I don't know if this has
>> something to do with ITK or if it's just basic c++. Whenever I try
>> to make an instance of gradient Im getting an undefined reference
>> Linker error:
>>
>> Linking CXX executable generateProblems.exe
>> CMakeFiles/generateProblems.dir/main.obj:main.cxx:(.text+0x288):
>> undefined reference to `gradient<it
>> k::Image<unsigned short, 3u> >::gradient()'
>> collect2: ld returned 1 exit status
>> mingw32-make[2]: *** [generateProblems.exe] Error 1
>> mingw32-make[1]: *** [CMakeFiles/generateProblems.dir/all] Error 2
>> mingw32-make: *** [all] Error 2
>>
>> Ive attached both .h and cxx class, hope this works.
>> thanks for any help.
>> lars
>>
>>
>>
>>
>>
>> _________________________________________________________
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>> <gradient.cxx>
>> <gradient.h>
>> _______________________________________________
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>> Insight-users at itk.org
>> http://www.itk.org/mailman/listinfo/insight-users
>
> --
> Gaëtan Lehmann
> Biologie du Développement et de la Reproduction
> INRA de Jouy-en-Josas (France)
> tel: +33 1 34 65 29 66    fax: 01 34 65 29 09
> http://voxel.jouy.inra.fr
>
>
>
>
>
>
>
>
>
> _________________________________________________________
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