undefined reference to `vtable for shutdown'

[JonB]

@JoeCFD

@SPlatten said in undefined reference to `vtable for shutdown':

@J-Hilk . that was the entire class, I've added virtual to the destructor prototype, rebuilding now.

@SPlatten
Let's be clear: you are now compiling with

public:
    explicit shutdown(const char* cpszText, QWidget* pParent = 0);
    virtual ~shutdown();

right?

[JoeCFD]

@JonB I did not see that one. Could be the case he changed it and did not save it.

[SPlatten]

@JonB , the only place the shutdown.cc.o exists is off the build directory which I am still deleting completely between rebuilds.

[SPlatten]

@JonB , I've changed these prototypes several times with the same result each time, presently they are:

public:
    shutdown(const char* cpszText, QWidget *pParent = 0);
    ~shutdown();

[JoeCFD]

@SPlatten this is wrong. You have always to have virtual in front of a destructor. Otherwise, you may have unpleasant memory leak in your apps.

[JonB]

@SPlatten
I am lost at this point. It might be that one of the experts knows better than I what situation you are in. You would have to wait for them to see this, perhaps later.

At this point, if I were you and I had nothing else to do I would probably take what you have and put it into a brand new, from scratch, standalone tiny project (maybe get rid of the .ui file too) and see if I could get it working as (a) a standalone Qt program (provide a main()) and (b) whatever you are doing for " I have added a class [to] one of the libraries" which I don't know about.

public:
    shutdown(const char* cpszText, QWidget *pParent = 0);
    ~shutdown();

I do think you should write virtual ~shutdown(); here, just in case.

[SPlatten]

@JoeCFD , ok, I've changed the constructor so it is prefixed with explicit and the destructor with virtual which goes back to how it was and I still have the same issue.

[SPlatten]

@JonB , I believe this issue is because the build process is using just cmake and hasn't been done with Qt Creator. I can't change it, its an old system that is evolving over time.

[SPlatten]

Just for completeness, here is the actual content of the CMakeLists.txt file:

cmake_minimum_required(VERSION 2.8.10)
include (flexelint) 

set (CMAKE_AUTOUIC ON)
set (CMAKE_AUTOMOC ON)
set (CMAKE_AUTORCC ON)
set (CMAKE_INCLUDE_CURRENT_DIR ON)

set (FORMS shutdown_ui)
set (HEADERS shutdown.h
             ui_shutdown.h)
set (sources shutdown.cc)
set (output vip_backend)
add_library(${output} STATIC ${sources})
find_package(Qt4 REQUIRED)
include(${QT_USE_FILE})
foreach(loop_var ${QT_LIBRARIES})
  string(REPLACE lib64 lib32 loop_var ${loop_var})
  set(QT_LIBRARIES_32 ${QT_LIBRARIES_32} ${loop_var})
endforeach(loop_var)
qt4_wrap_ui(UI_HEADERS ${FORMS})
qt4_wrap_cpp(MOC_SRCS ${HEADERS})
target_link_libraries(${output} ${QT_LIBRARIES_32})
add_flint(${output})

I have no idea what flexelint is or what it does, same is true of add_flint(${output}).

[JoeCFD]

@SPlatten forget about Qt Creator. Try to build it from command line
Delete build folder
Create build folder
From build folder cmake ${myvariable}
From build folder make VERBOSE=1
add verbose to see more build details.

[SPlatten]

@JoeCFD , that is exactly all I am doing. Also cmake is version 2.8.10.2

rm -R build
mkdir build
cd build
cmake ${myvariable}
make 

In the CMakeLists.txt file I have:

set (CMAKE_VERBOSE_MAKEFILE ON)

[JoeCFD]

@SPlatten Jesus, your cmake is old.

[SPlatten]

@JoeCFD , its very frustrating, its very unusual to find a company these days that are so behind on revisions.

[JoeCFD]

@SPlatten
rm -R build
mkdir build
cd build
cmake ${myvariable}
make VERBOSE=1

[SPlatten]

@JoeCFD , doing that now.

[JoeCFD]

@SPlatten As Jon commented, you can comment the destructor code out and build. It is a small leak. Not a big deal. shutdown is not a good name for class. Try to avoid to use any system command names as your class names. Name it for example ShutdownWindow.

[SPlatten]

@JoeCFD , will try this now.

[SPlatten]

@JoeCFD , output has changed:

../../(usage.cc.o): In function 'shutdownNotice(char cont*)':
vip_system.cc:(.text+0xe1): undefined reference to `vtable for shutdown'
vip_system.cc:(.text+0xe9): undefined reference to `vtable for shutdown'
vip_system.cc:(.text+0x100): undefined reference to `vtable for shutdown'
vip_system.cc:(.text+0x108): undefined reference to `vtable for shutdown'
../../(shutdown.cc.o): In function 'shutdown::shutdown(char cont*, QWidget*)':
shutdown.cc:(text+0x3a): undefined reference to `vtable for shutdown'
../../(shutdown.cc.o):shutdown.cc(.text+0x41): more undefined references to `vtable for shutdown' follow collect2 ld returned 1 exit status

[JoeCFD]

are you building on Linux, right? If yes, change your class name with ShutdownWindow (do not forget the ui file).

[SPlatten]

@JoeCFD , yes Linux...will give it a go (renaming I mean).