CMake: new subclass of dependency "unresolved external symbol" - qt

Question

I have a problem subclassing a VTK class, but I think the problem could be linked to any kind of library.
I did a vtkInteractorStyleImage subclass, just overriding a method:
#ifndef dcmInteractorStyleImage_h
#define dcmInteractorStyleImage_h
#include "vtkInteractionStyleModule.h" // For export macro
#include "vtkInteractorStyleImage.h"
class VTKINTERACTIONSTYLE_EXPORT dcmInteractorStyle : public vtkInteractorStyleImage
{
public:
static dcmInteractorStyle *New();
vtkTypeMacro(dcmInteractorStyle, vtkInteractorStyleImage);
virtual void OnLeftButtonDown();
void PrintSelf(ostream& os, vtkIndent indent);
};
#endif
The thing is I use it in a Qt class. So I include this in my CMakeLists.txt (simplified):
set(GENERIC_VIEW_CPP
View/UI/dcminteractorstyle.cpp # my new class
)
SET(GENERIC_VIEW_H
View/UI/dcminteractorstyle.h # my new class
)
add_library(generic ${GENERIC_VIEW_CPP} ${GENERIC_VIEW_H})
...
add_library(ui_qt ${UI_QT_CXX}
${UI_FORM_HEADERS} ${UI_RESOURCES_RCC}
${MODEL_WRAPPED_HEADERS}
${GENERIC_VIEW_CPP} ${GENERIC_VIEW_H} #necesary here?
)
qt5_use_modules(ui_qt Core Gui Widgets)
----------------------------------------------------------
# VTK
find_package(VTK REQUIRED)
include(${VTK_USE_FILE})
# ITK
find_package(ITK REQUIRED)
include(${ITK_USE_FILE})
if (ITKVtkGlue_LOADED)
find_package(VTK REQUIRED)
include(${VTK_USE_FILE})
else()
find_package(ItkVtkGlue REQUIRED)
include(${ItkVtkGlue_USE_FILE})
set(Glue ItkVtkGlue)
endif()
------------------------------------------------
set_source_files_properties(${UI_RESOURCES_RCC} PROPERTIES GENERATED ON)
add_executable(UtilidadDICOM WIN32 main.cpp ${UI_RESOURCES_RCC})
target_link_libraries(UtilidadDICOM
model
ui_qt
generic
${Glue}
${VTK_LIBRARIES}
${ITK_LIBRARIES}
)
The error trying to compile:
ui_qt.lib(viewerwidget.cpp.obj):-1: error: LNK2019: unresolved
external symbol "public: static class dcmInteractorStyle * __cdecl
dcmInteractorStyle::New(void)" (?New#dcmInteractorStyle##SAPAV1#XZ)
referenced in function "public: static class vtkSmartPointer __cdecl vtkSmartPointer::New(void)"
(?New#?$vtkSmartPointer#VdcmInteractorStyle####SA?AV1#XZ)
ui_qt is a library declared in CMake, as you can see above.
Any ideas? Thank you.

Answer 1

Short answer is that your class is not being linked. Try seeing the value in generic just before linking it to your executable. Do a message just before target_link_libraries:
MESSAGE(${generic})
and see if the generic.lib is actually being linked.