[SOLVED] The program has unexpectedly finished

[sftpck]

Hello.
I created a new application project (qt widgets) and add 2 lines of code after QApplication a(argc, argv);:

@
QMessageBox::critical(NULL, "test", "test");
exit(0);
@

Program compiles and runs. But sometimes QT creator shows "The program has unexpectedly finished" and that the executable has crashed. It is random and happens on debug/release with gcc and llvm/clang. Kubuntu 64bits machine with QT 5.3.

@
#include "mainwindow.h"
#include <QApplication>
#include <QMessageBox>

int main(int argc, char *argv[])
{
QApplication a(argc, argv);

QMessageBox::critical(NULL, "test", "test");
exit(0);

MainWindow w;
w.show();

return a.exec();

}
@

I found this site: http://blogs.kde.org/node/3919 about how to crash (almost) every Qt/KDE, but it didn't help much.

Any help is appreciated.
Thank you.

[arsinte_andrei]

can you add on your main
@void myMessageOutput(QtMsgType type, const QMessageLogContext &context, const QString &msg){
QByteArray localMsg = msg.toLocal8Bit();
switch (type) {
case QtDebugMsg:
fprintf(stderr, "Debug: %s (%s:%u, %s)\n", localMsg.constData(), context.file, context.line, context.function);
break;
case QtWarningMsg:
fprintf(stderr, "Warning: %s (%s:%u, %s)\n", localMsg.constData(), context.file, context.line, context.function);
break;
case QtCriticalMsg:
fprintf(stderr, "Critical: %s (%s:%u, %s)\n", localMsg.constData(), context.file, context.line, context.function);
break;
case QtFatalMsg:
fprintf(stderr, "Fatal: %s (%s:%u, %s)\n", localMsg.constData(), context.file, context.line, context.function);
abort();
}
}

int main(int argc, char *argv[]){
qInstallMessageHandler(myMessageOutput);
QApplication app(argc, argv);
........................ and yu other lines
@
now maybe you can trace your program also use debug mode any error like c passing arg? or something similar??

[sftpck]

Thank you for your reply arsinte_andrei.

I added the code you posted, but it is never called when the application crash.

[sftpck]

Just tested with a Windows machine (Windows Vista 64bits) without any problems.
Also tested with a Ubuntu machine and got the same "The program has unexpectedly finished” problem.

[sftpck]

Changed line:
@
exit(0);
@

to:

@
return 0;
@

And no more “The program has unexpectedly finished” crash.

According to "stackoverflow":http://stackoverflow.com/questions/461449/return-statement-vs-exit-in-main

bq. When I call return in main(), destructors will be called for my locally scoped objects. If I call exit(), no destructor will be called for my locally scoped objects!bq.