[CMake] CMAKE -- compiling questions

[Bill Hoffman]

On 5/20/2010 8:48 AM, Michael Hertling wrote:
> On 05/20/2010 10:58 AM, Lucian Goron wrote:
>> I now have lucid lynx and I am struggling to get my old code to work on this
>> system
>> anyway, when I compile some of it I get:
>>
>> lucian at schwarz:~/work/ransac$ make
>> Linking CXX executable elevationMap
>> CMakeFiles/elevationMap.dir/home/lucian/work/common/CommonVTKRoutines.cc.o:
>> In function `Create2xRenderWindowAndInteractorMovie(vtkRenderer*,
>> vtkRenderer*, char const*, char const*, int, int, int)':
>> CommonVTKRoutines.cc:(.text+0xa720): undefined reference to
>> `vtkFFMPEGWriter::New()'
>> CMakeFiles/elevationMap.dir/home/lucian/work/common/CommonVTKRoutines.cc.o:
>> In function `Create4xRenderWindowAndInteractorMovie(vtkRenderer*,
>> vtkRenderer*, vtkRenderer*, vtkRenderer*, char const*, char const*, int,
>> int, int)':
>> CommonVTKRoutines.cc:(.text+0xad84): undefined reference to
>> `vtkFFMPEGWriter::New()'
>> CMakeFiles/elevationMap.dir/home/lucian/work/common/CommonVTKRoutines.cc.o:
>> In function `CreateRenderWindowAndInteractorMovie(vtkRenderer*, char const*,
>> char const*, int, int, int)':
>> CommonVTKRoutines.cc:(.text+0xb6e3): undefined reference to
>> `vtkFFMPEGWriter::New()'
>> collect2: ld returned 1 exit status
>> make[2]: *** [elevationMap] Error 1
>> make[1]: *** [CMakeFiles/elevationMap.dir/all] Error 2
>> make: *** [all] Error 2
>> lucian at schwarz:~/work/ransac$
>>
>> I know, I have a problem with the ffmpeg library...
>> But my questions is, in someway very stupid, related to the
>>
>> (.text+0xa720)
>>
>> part, what does it mean, wasn't it supposed to show me the line number where
>> the error occurs in
>>
>> /home/lucian/work/common/CommonVTKRoutines.cc
>>
>> how can I see the line numbers ?
>
> Line number information must be enabled when compiling, e.g. by means of
> GCC's option "-g". Without it, you will just get offsets into the object
> code instead, like the 0xa720 above; besides, "text" is an ancient *nix
> term for a memory segment containing program code, in contrast to data
> segments. Typically, the "-g" option will be spefified when setting the
> CMAKE_BUILD_TYPE to "Debug" or "RelWithDebInfo", but see the various
> CMAKE_<LANG>_FLAGS, too.
>
If you link in the library in VTK that has vtkFFMPEGWriter in it, all 
the problems should go away.  I would not worry about the .text stuff 
right now.  It is just the place that is referencing the symbols you 
don't have.  Once you have the symbols, then you won't have a problem.

-Bill