I got debug error when try to show simple widget subclass
inside dll

error
Qt Code: 
  1. Debug Error
  2. QWidget:Cannot create a QWidget when no GUI is being used
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How make GUI being used?

here simple test code.
Qt Code: 
  1. QCoreApplication *coreApp ;
  2. void MyThread::run()
  3. {
  4.  
  5. 	int notUse;
  6. 	coreApp = new QCoreApplication(notUse,0);
  7.  
  8. 	QString fileName = qApp->applicationDirPath()+"/test.txt";
  9. 	qDebug(fileName.toLocal8Bit());
  10. 	//QFile file(fileName,coreApp);
  11. 	//file.open(QIODevice::ReadWrite);
  12. 	//file.write("Hello's world",sizeof("Hello's world"));
  13. 	MyGui gui;
  14. 	gui.show();
  15. 	coreApp->exec();
  16. }
  17.  
  18. BOOL APIENTRY DllMain( HMODULE hModule,
  19. 					  DWORD  ul_reason_for_call,
  20. 					  LPVOID lpReserved
  21. 					  )
  22. {
  23. 	switch (ul_reason_for_call)
  24. 	{
  25. 	case DLL_PROCESS_ATTACH:
  26. 		{
  27. 			MyThread *myThread = new MyThread;
  28. 			myThread->start();
  29. 			break;
  30. 		}
  31. 	case DLL_THREAD_ATTACH:
  32. 	case DLL_THREAD_DETACH:
  33. 	case DLL_PROCESS_DETACH:
  34. 		break;
  35. 	}
  36. 	return TRUE;
  37. }
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Show gui at DLL_PROCESS_ATTACH
also got same debug message
Thank.