[Cmake] RE: [Insight-developers] (ITK) Build Errors terminus.kitware -- W inXP-VC60, library rebuil ds

[Bill Hoffman]

OK, With DevStudo 6 and 7, static libraries can not depend on other static libraries.   By adding the dependency, it causes the project to link the two libraries together.

So, if you have this:

libA dependsOn libB, libC
libB dependsOn libC
exeC dependsOn libB, libA, libC

Then when you link exeC, you will get duplicate symbol warnings, because
it will have the .o files from C duplicated in libB and libA.

So, with visual studio 6 and 7, you can not chain static libraries.
However, if you build an executable that uses the libraries, it will
chain correctly.

If you did the "add files to project", for all the depend information, you
would see the problem.   If you only do it for one of them it appears to work,
but if you look closely, you will see that it is creating combo libraries.

So, for your example, if you built IOTests, it would correctly build both
the DICOMParser and the IO library.   But, building the IO library will
not cause the DICOMParser to rebuild.


-Bill


At 04:02 PM 3/17/2003, Miller, James V (Research) wrote:
>Well here a test that I ran the other day.  It happens to mimic the problem that Matt was having.  In ITK, there is a library under Utilities called DICOMParser.  In Code/IO is there is a class that uses this library called itkDICOMImageIO2. If I make a change to Utilities/DICOMParser/DICOMFile.cxx and tell DevStudio to rebuild the IO library, it does not recompile DICOMFile.cxx.  It instead thinks that Utilities/DICOMParser is up to date and links the IO library using the old DICOMParser lib.
> 
>Matt added the DICOMParser library to the IO project using "Add Files To Project..." and then a change to DICOMFile.cxx does cause the IO library to build.
> 
>Otherwise, I would fathom that you are correct in that the incremental linker is trying to incrementally link an old executable with a new library and complaining.
> 
>Sorry for the specific example. But I am in the rush to talk to someone.....
> 
>Jim
> 
>-----Original Message-----
>From: Ken Martin [mailto:ken.martin@kitware.com]
>Sent: Monday, March 17, 2003 3:11 PM
>To: 'Miller, James V (Research)'; 'Insight-developers (E-mail)'; 'CMake developers (E-mail)'
>Subject: RE: [Insight-developers] (ITK) Build Errors terminus.kitware -- WinXP-VC60, library rebuil ds
>
>I just checked and as far as I can see CMake is setting up the target dependencies (and chaining them) correctly for both VS6 and VC7. (it is easy to verify from VS just look at the project dependencies). Having seen this type of problem before on occasion, my suspicion is that this is a bug in the VS incremental linker or VS dependency checks.  Unfortunately the offending dashboard was cleaned so there is little remaining evidence. Looking at the dashboard it seems clear that ITKCommon was rebuilt (the symbols are missing as they should be) the problem seems to be that some examples still think that the symbols should be there. So either the executable is screwed up (VS is trying to relink the executable) or the specific test .obj file (Smooth something or another in this case) has not been rebuilt, but that is a VS dependency issue. It would have been nice if we could have checked if the Smooth&obj was up to date or not.
>
> 
>
>Ken
>
> 
>
> 
>
>-----Original Message-----
>From: insight-developers-admin@public.kitware.com [mailto:insight-developers-admin@public.kitware.com] On Behalf Of Miller, James V (Research)
>Sent: Monday, March 17, 2003 2:18 PM
>To: Insight-developers (E-mail); CMake developers (E-mail)
>Subject: [Insight-developers] (ITK) Build Errors terminus.kitware -- WinXP-VC60, library rebuil ds
>
> 
>
>The build errors on terminus.kitware are referencing methods that I removed from the system on Friday.  These symbols were never used, so I deleted them to simplify the code.
>
> 
>
>Since we have these build errors, it looks VC6 did not rebuild all the libraries or an old object file is lying around.
>
> 
>
>The reason I bring this up on the list(s) is that we have had a lot of problems recently with VC6 building applications (examples) where the dependent libraries are not being rebuilt.  Here is an example:  change some code in library A.  Library B links with library A.  Executable C links with library B.  If you just tell VC6 to build executable C, then library A does not get rebuilt.  If you build from the top using the ALL_BUILD target, then everything works fine. I think Matt discovered if he added the other libraries to the particular projects (using "Add files to project"), then the rebuilds are triggered properly.  However, this information is lost the next time CMake is run.
>
>Have other people seen this? Can CMake add the link libraries that an executable uses that are also built by the workspace to the dependent projects? Or is this necessary?
>
>I think I have seen this same behavior on VC7.
>
>Jim Miller 
>_____________________________________
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