[Paraview] mysterious linker error for custom library in custom PV Plugin

[Takuya OSHIMA]

I guess 'extern "C"' is missing in the declaration of fioOpen?

Takuya

Takuya OSHIMA, Ph.D.
Faculty of Engineering, Niigata University
8050 Ikarashi-Ninocho, Nishi-ku, Niigata, 950-2181, JAPAN

From: Christine Corbett Moran <corbett at physik.uzh.ch>
Subject: [Paraview] mysterious linker error for custom library in custom PV Plugin
Date: Thu, 3 Mar 2011 16:57:48 +0100

> I have a problem with building/linking to an external library I've called
> libfio. The library builds, and I can link programs against it from the
> command line. However my final plugin always comes up with a "ld: symbol(s)
> not found". I have several other libraries which are linked against just
> fine in my plugin, it is only this one which creates a problem.
> 
> I'm on OS X 10.6, using gcc version 4.2.1 (Apple Inc. build 5664). I have
> tried building it both as a shared and static library, from both CMake and
> externally (then linking from within CMake). I have several other libraries
> I rely on which function perfectly well under any of the previous setups:
> {shared,static} x {built within plugin cmake, built externally} x {c,cxx}.
>  However with this set of .c files I always get a linking error, and it's
> the same for any of the previous permutations. Under any configuration I'm
> able to link against it from the command line. That is to say for the
> example for a shared library built within the PV plugin CMake: libfio.dylib
> is created within my build directory ParaViz_build, and doing e.g.  gcc
> grafic2csv.c -lfio
> -L/Users/corbett/Documents/Projects/pvaddons/ParaViz/ParaViz_build/  -o
> grafic2csv has no linking errors, where grafic2csv contains the identical
> code which later offends the linker within my plugin (see below for sample).
> 
> Example make output for a shared library built within the PV Plugin CMake:
> ...
> [ 11%] Built target TipsyHelpers
> [ 13%] Building C object CMakeFiles/fio.dir/fio/fio.c.o
> [ 14%] Building C object CMakeFiles/fio.dir/fio/romberg.c.o
> Linking C shared library libfio.dylib
> [ 14%] Built target fio
> [ 16%] Building C object CMakeFiles/SQLitelib.dir/sqlitelib/sqlite3.c.o
> Linking C static library libSQLitelib.a
> [ 16%] Built target SQLitelib
> ..
> [ 98%] Building CXX object
> CMakeFiles/AstroVizPlugin.dir/AstroVizPlugin_Plugin.cxx.o
> [100%] Building CXX object
> CMakeFiles/AstroVizPlugin.dir/moc_AstroVizPlugin_Plugin.cxx.o
> Linking CXX shared library libAstroVizPlugin.dylib
> Undefined symbols:
>   "fioOpen(char const*, double, double)", referenced from:
>       vtkGraficReader::RequestData(vtkInformation*, vtkInformationVector**,
> vtkInformationVector*)in vtkGraficReader.cxx.o
> ld: symbol(s) not found
> collect2: ld returned 1 exit status
> make[2]: *** [libAstroVizPlugin.dylib] Error 1
> make[1]: *** [CMakeFiles/AstroVizPlugin.dir/all] Error 2
> make: *** [all] Error 2
> 
> 
> 
> Example CMake for building a static library with the PV Plugin CMake:
> 
> ADD_LIBRARY(
> fio
> STATIC
> fio/fio.c
> fio/romberg.c
> )
> SET_TARGET_PROPERTIES(fio PROPERTIES LINKER_LANGUAGE C)
> SET_TARGET_PROPERTIES(fio PROPERTIES COMPILE_FLAGS "-fPIC")
> 
> TARGET_LINK_LIBRARIES(
> AstroVizPlugin
> fio
> TipsyHelpers
> SQLitelib
> )