Qt Debuging Tips

Output:

• qDebug() : e.g. qDebug() << "Stuff:" <<>
• qCritical(): e.g. qCritical("no more memory");
• qFatal();
• qWarning()

Assertion:

• Q_ASSERT()
• Q_ASSERT_X(): this can print the line where assertion fail

Check pointer:

• Q_CHECK_PTR()

Run qmake again:

• error like "vtbl, _vtbl": this might be related to meta-object compiler, check if using Q_OBJECT correctly, make sure the signal/slot syntax (declaration/implementation), and re-run qmake.

Also read the Qt 4.5 Debug Documentation.