linking vtk library fail: undefined reference to `vtksys::SystemToolsManager::SystemToolsManager()

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1

I have a file a.cpp consisting of the following lines:

#include <vtkVersion.h> 
int main(){}

I try to build it with vtk 9.3

g++ -L/usr/local/lib -I/usr/local/include/vtk-9.3   -lvtksys-9.3   -o a.out  a.cpp

but it reports:

/usr/bin/ld: /tmp/ccnbq1jH.o: in function `__static_initialization_and_destruction_0(int, int)':
a.cpp:(.text+0x61): undefined reference to `vtksys::SystemToolsManager::SystemToolsManager()'
/usr/bin/ld: a.cpp:(.text+0x76): undefined reference to `vtksys::SystemToolsManager::~SystemToolsManager()'
collect2: error: ld returned 1 exit status

I try to see if the symbols are there

nm --demangle --dynamic --defined-only --extern-only /usr/local/lib/libvtksys-9.3.so|grep vtksys::SystemToolsManager

and it shows:

0000000000054746 T vtksys::SystemToolsManager::SystemToolsManager()
0000000000054746 T vtksys::SystemToolsManager::SystemToolsManager()
000000000005477e T vtksys::SystemToolsManager::~SystemToolsManager()
000000000005477e T vtksys::SystemToolsManager::~SystemToolsManager()

That means the symbol is there. What is the problem? However, when I build my code using vtk-6.3, there is no problem.

g++ -L/usr/lib/x86_64-linux-gnu -I/usr/include/vtk-6.3   -lvtksys-6.3   -o a.out  a.cpp
2

Try changing your a.cpp as follows, and you will probably see the same link error with VTK 6.3:

#include <vtksys/SystemTools.hxx> 
int main(){}

As for the cause of the eror, if a.cpp needs to link to libvtksys-9.3, then it needs to come before it on the command line:

g++ -L/usr/local/lib -I/usr/local/include/vtk-9.3 a.cpp -lvtksys-9.3 -o a.out

The reason that merely including SystemTools.hxx causes a link dependency is the following line in this header:

// This instance will show up in any translation unit that uses
// SystemTools. It will make sure SystemTools is initialized 
// before it is used and is the last static object destroyed.
static SystemToolsManager SystemToolsManagerInstance;

From the gcc man page:

  -l library

     It makes a difference where in the command you write this option; the
     linker searches and processes libraries and object files in the order
     they are specified.  Thus, foo.o -lz bar.o searches library z after
     file foo.o but before bar.o.  If bar.o refers to functions in z, those
     functions may not be loaded.
3

And, in general, the only supported way to build against VTK is to use CMake and the targets that VTK exports (in addition to any vtk_module_autoinit() calls that may be needed to use vtkObjectFactory-using classes).

4

Thank you very much everyone.

I forget that order of -l is important.

For those who might have this problem:

I have this problem because the library liggghts (GitHub - CFDEMproject/LIGGGHTS-PUBLIC: official release of the LIGGGHTS® DEM software by DCS Computing. For further info, forums, and bug reports, please visit http://www.cfdem.com. For the DEM software Aspherix® by DCS Computing that replaces LIGGGHTS, please visit https://www.aspherix-dem.com/) cannot be built against the latest VTK library using the legacy method make auto. By changing the order in the Makefile.auto,

        TMP := $(shell $(ECHO) '$Hinclude <vtkVersion.h> \n int main(){}' > $(TMPFILE) && $(CXX) $(EXTRA_LIB) $(VTK_LIB) $(VTK_INC) $(EXTRA_ADDLIBS)  -lvtksys$(VTK_APPENDIX) $(CCFLAGS) -xc++ -o /dev/null  $(TMPFILE) 2>> $(AUTO_LOG_FILE) && echo 0 || echo -1)

to

        TMP := $(shell $(ECHO) '$Hinclude <vtkVersion.h> \n int main(){}' > $(TMPFILE) && $(CXX) $(EXTRA_LIB) $(VTK_LIB) $(VTK_INC) $(EXTRA_ADDLIBS) $(TMPFILE) -lvtksys$(VTK_APPENDIX) $(CCFLAGS) -xc++ -o /dev/null  2>> $(AUTO_LOG_FILE) && echo 0 || echo -1)

everything works.