undefined reference to `DummyInputMethod3::staticMetaObject' when building maliit framework on windows

Question

So I'm trying to build Maliit Framework https://github.com/maliit using Qt Creator on a Windows machine. I have fixed several windows compatibility issues so far: https://github.com/RHawkeyed/framework. But now I get this error: undefined reference to 'DummyInputMethod3::staticMetaObject' in qobject.h

From answers to similar problems I found through google, this is often caused by not defining the qobject in a header, forgetting to add Q_OBJECT macro or moc not running properly. This does not seem to be the case here as DummyInputMethod3 is defined in its own header:

class DummyInputMethod3 : public MAbstractInputMethod
{
    Q_OBJECT

    ...

And moc_dummyinputmethod3.cpp is generated in the path I would expect.

Also the header file is listed in the pro file as it should be:

HEADERS += \
    dummyimplugin3.h \
    dummyinputmethod3.h \

Any ideas about what might be wrong?

Getting the error when compiling this:

https://github.com/RHawkeyed/framework

in Qt Creator 3.5.0 using MinGW 4.9.2 32bit and Qt 5.5.0

The qmake files make use of several linux commands so I have added cygwin https://www.cygwin.com/ to the system path.

Compiling with msvc

I am not bound to a specific compiler, I just need to compile for windows. Compiling with msvc is perfectly acceptable. Actually I started out trying to compile with msvc, but after running into a number of problems and seeing suggestions that it is meant to be compiled with mingw I tried that instead. Anyway I can now compile up to the same error in both mingw and msvc:

https://github.com/RHawkeyed/framework

in Qt Creator 3.5.0

Qt 5.5

MSVC2013 32 bit

If everything else is OK, then MAbstractInputMethod does not derive from QObject. Alas, please first delete the entire build folder (build-... above your source folder) and build again. — Kuba hasn't forgotten Monica
@KubaOber I have already cleaned, run qmake and rebuild a couple of times, just tried again in a new build folder, same problem. And it does derive from QObject class MAbstractInputMethod: public QObject { Q_OBJECT — RHawkeyed
I'll take a peek, but since this is for fun I won't touch MinGW with a long pole. I'll see if it can compile with MSVC 2012 or 2015. — Kuba hasn't forgotten Monica
@KubaOber Hi :) Have you had a chance to give it a try yet? Compiling with msvc is perfectly fine, I actually tried that first. But after I ran into several compilation errors and saw mingw mentioned in one of the .pro files, I tried mingw instead. I have made a few more changes and I can now get it to compile up to the same error with both compilers. I normally use msvc2013, but I also tried compiling with msvc2012 and it behaves the same. — RHawkeyed

RHawkeyed RHawkeyed · Accepted Answer · 2015-10-20T11:50:04

I am fairly certain I have solved this particular problem correctly. Import/export is needed for windows dlls. It happens automatically on linux. So much for maliit being cross platform.

I still don't have maliit keyboard working properly. The example app starts, however I can't get the keyboard to show. Anyway that is for another question, that is if I don't just abandon this altogether.

My current progress is on github:

https://github.com/RHawkeyed/framework

https://github.com/RHawkeyed/plugins

undefined reference to `DummyInputMethod3::staticMetaObject' when building maliit framework on windows

1 Answers