error: undefined reference to `QVTKWidget::QVTKWidget(QWidget*, QFlags<Qt::WindowType>)'

surajj4837

I m using Qt5.15 in Ubuntu 20.04. I want to use PCL to visualise point cloud data. To get PCL runnig with Qt, VTK library is also required. So in my system I have PCL 1.10 and VTK 7.1.1. I have taken sample code for testing the setup from here. I m getting following error:

error: undefined reference to `QVTKWidget::QVTKWidget(QWidget*, QFlags<Qt::WindowType>)'

Any suggestion for resolving this?

jsulm

@surajj4837 said in error: undefined reference to `QVTKWidget::QVTKWidget(QWidget*, QFlags<Qt::WindowType>)':

Any suggestion for resolving this?

Link against the VTK library

Anonymous_Banned275

This could be a good time to take a look at Qt SUB_DIRS.
It does most of the grunt work for you.
It manages library source code , links to library...
However you still have to add source reference (include header) to
your library. Lack of it gives you "undefined reference " error.

SUB_DIRS even lets you reuse existing code - importing from github.

surajj4837

@jsulm I followed steps given here for building vtk8.1.0 and linking it with Qt.

Christian Ehrlicher

@surajj4837 said in error: undefined reference to `QVTKWidget::QVTKWidget(QWidget*, QFlags<Qt::WindowType>)':

and linking it with Qt.

This link never tells you anything how to link against the VTK library. See qmake documentation on how to link against libs: LIBS
And forget about SUB_DIRS - it's not needed here at all (aart from the fact that even the name is wrong - it's SUBDIRS)

surajj4837

@Christian-Ehrlicher I m using cmake build system.

Christian Ehrlicher

Then take a look at find_library and target_link_libraries... There are enough examples out there for cmake.

surajj4837

I think the problem is, I m copying the libQVTKWidgetPlugin.so in /plugins/designer/ directory of Qt but the qt creator is not able to recognize it.

jsulm

@surajj4837 If it is a plug-in for QtCreator then you need to copy it to the QtCreator plugin folder.

surajj4837

Official doc says libQVTKWidgetPlugin.so is required to be copied to plugins/designer directory, I have seen many setup tutorial pages which convey the same like this and this.