Build a JNI DLL using MINGW

问题

I am trying to create a DLL that will call Qt (currently I can't use Jambi for the functionality I need). I have a simple Java method:

public final native int createChild(int handle);

I created C project in Visual Studio Express 2010 and was able to build the DLL.

Then I created a project in Qt creator and moved my sources there. I tried to configure the build to a best of my knowledge but all I get is:

java.lang.UnsatisfiedLinkError: tools.proofofconcept.control.EmbedderComposite.createChild(I)I

My guess is that symbol is not properly exported from DLL. I added -D_JNI_IMPLEMENTATION_ linker arg:

g++ -D_JNI_IMPLEMENTATION_  -enable-stdcall-fixup -Wl,-enable-auto-import -Wl,-enable-runtime-pseudo-reloc -shared -mthreads -Wl -Wl,--out-implib,debug\libqt_integration.a -o debug\qt_integration.dll debug/dllmain.o debug/nativecode.o debug/qmfcapp.o debug/qwinwidget.o debug/moc_qwinwidget.o  -L"c:\Qt\2010.05-rc1\qt\lib" -lQtGuid4 -lQtCored4 

回答1:

I should've added following argument:

-Wl,--kill-at

It will change exported symbols format.

回答2:

If you are using Qt make sure which configuration is used. By default "default" configuration is used (folder "mkspecs/default") and for win32 this causes "UnsatisfiedLinkError".

来源：https://stackoverflow.com/questions/3689074/build-a-jni-dll-using-mingw