Linking Error when Creating DLL with Visual Studio

[stretchtiberius]

Thank you for your help. That all makes since to me. However, the following code should be acceptable right?

int test()
{
    int argc = 1;
    char *arg[] = {"test"};
    QApplication app(argc, argv);
    QPushButton quit("Quit");
    quit.resize(75, 30);
    quit.setFont(QFont("Times", 18, QFont::Bold));
    QObject::connect(&quit, SIGNAL(clicked()), &app, SLOT(quit()));
    quit.show();
    return app.exec();
}

int test()
{
    int argc = 1;
    char *arg[] = {"test"};
    QApplication app(argc, argv);
    QPushButton quit("Quit");
    quit.resize(75, 30);
    quit.setFont(QFont("Times", 18, QFont::Bold));
    QObject::connect(&quit, SIGNAL(clicked()), &app, SLOT(quit()));
    quit.show();
    return app.exec();
}

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I tried Qt Creator and this code did compile. However, when I run the project with Visual Studio (converting with qmake -t vclib), I receive the same linking errors. Another interesting discover is that if I point Qt Creator to the Qt files it came with, a .dll is produced. If I point it to the Qt files I compiled I only get a .lib file. Why is that? In any case I really need to be able to compile with Visual Studio. I have also discovered that a the above function will compile with Visual Studio if I make the function static. Naturally this also will not do. Any more ideas?

[talk2amulya]

I think u r doing it wrong..QApplication and QCoreApplication are only used in executables..when u r creating a dll or lib, u dont use them..I'd suggest u make two projects in Visual studio..one u set as a startup project which will produce an exe, in there, u create a QApplication..in other project u create a dll and u use it with the exe

[stretchtiberius]

Actually, really what I would like to do is create a dll from C++ containing the GUI and have a Java backend load the GUI via JNI. It would be great to keep all the Qt stuff in C++.

[talk2amulya]

then why r u tyring all that.. u should go ahead and create a container and put all the gui in it..export it..if u wanna see how its all going..u'll hv to create an exe and use QApplication..when u hv all u want..remove the main function part..create a dll out of all that and use JNI..i dont think it'll be a big issue