DLL problem im confuse..

[triperzonak]

first can you guys check if what i did is right?

in my .h

#ifdef MYDLL
#define MYDLLAPI Q_DECL_EXPORT 
#else 
#define MYDLLAPI
#endif 
 
#include <QDialog>
 
class MYDLLAPI MyClass : public QDialog
{
Q_OBJECT
public:
	MyClass(QWidget * parent = 0, Qt::WFlags f = 0 );
public slots:
	void showMsg();
}
 
/*i dont have a UI*/

#ifdef MYDLL
#define MYDLLAPI Q_DECL_EXPORT 
#else 
#define MYDLLAPI
#endif 

#include <QDialog>

class MYDLLAPI MyClass : public QDialog
{
Q_OBJECT
public:
	MyClass(QWidget * parent = 0, Qt::WFlags f = 0 );
public slots:
	void showMsg();
}

/*i dont have a UI*/

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in my .pro

/*i added*/
CONFIG += dll release
TEMPLATE = lib
DEFINES = MYDLL

/*i added*/
CONFIG += dll release
TEMPLATE = lib
DEFINES = MYDLL

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this will create a myclass.a and myclass.dll (im using windows mingw)

it will be use by the other application
here's what I've done

in my app .pro i added

LIBS += "<path to my lib>\libmyclass.a"
INCLUDEPATH = "<path to includes>"

LIBS += "<path to my lib>\libmyclass.a"
INCLUDEPATH = "<path to includes>"

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in my app code

#include "myclass.h" //from the include of dll
 
/*some includes*/
 
int main (int argc, char * argv [])
{
QApplication app( argc, argv );
QLibrary *loadmylibrary = new QLibrary("myclass"); //my dll
loadmylibrary->setLoadHints(QLibrary::ResolveAllSymbolsHint);
loadmylibrary->load();
if (loadmylibrary->isLoaded() == false)
    qDebug()<<"error not loaded";
 
else
{
qDebug()<<"loaded";
MyClass *mycls; //from my dll
 
mycls->showMsg();
}
 
app.connect( &app, SIGNAL( lastWindowClosed() ), &app, SLOT( quit() ) );
return app.exec();
}

#include "myclass.h" //from the include of dll

/*some includes*/

int main (int argc, char * argv [])
{
QApplication app( argc, argv );
QLibrary *loadmylibrary = new QLibrary("myclass"); //my dll
loadmylibrary->setLoadHints(QLibrary::ResolveAllSymbolsHint);
loadmylibrary->load();
if (loadmylibrary->isLoaded() == false)
    qDebug()<<"error not loaded";

else
{
qDebug()<<"loaded";
MyClass *mycls; //from my dll

mycls->showMsg();
}

app.connect( &app, SIGNAL( lastWindowClosed() ), &app, SLOT( quit() ) );
return app.exec();
}

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my applications show:

loaded

QWidget: Must construct a QApplication before a QPaintDevice

then the messagebox will not show from the dll.. how can i solve this?

[jpn]

Why are you linking to and loading the same library again at runtime?

[triperzonak]

thanks bro..

i remove the QLibrary and rebuild my apps and dll.. it is now working.

is there a problem if i build a dll from static build of qt?..