QCoreApplication, instead of QApplication, is enough to have a Qt event loop
README.text in wt/examples/wtwithqt/lib mentions that a QApplication object is needed if Qt event loop is required. However QCoreApplication is enough and should be preferred for most of the applications since QApplication pulls in QtGui which most likely won't be necessary in a Wt application.
The hello.C file of the example application in wt/examples/wtwithqt #includes and instantiates a QApplication instance in main() if the the relevant lines are uncommented. These should be changed to QCoreApplication.
Updated by Kayra Akman over 8 years ago
The change to resolve this issue introduced a small error in a comment.
In https://github.com/kdeforche/wt/blob/master/examples/wtwithqt/hello.C, line 37 reads:
// Needed when using WQCoreApplication with Qt eventloop = true
There exists a WQApplication class but not WQCoreApplication.