Question

I use CMake to create my projects. In the project I use mainly Qt C++ and some MFC functions for hardware interface. Does it make any sense to use try/catch e->ReportError() or some other exception statements in the code?

Answer 1

You can of course use exceptions together with Qt. The question is just, how useful they are. As an example, consider the following class

class Thrower : public QObject
{
    Q_OBJECT
public slots:
    void throwException()
    {
        throw 42;
    }
};

The exception is thrown inside a slot. To catch this exception, you have to wrap the
signal, which triggers the slot, in a try block, e.g.

class Catcher : public QObject
{
    Q_OBJECT
public:
    Catcher(Thrower* t)
    {
        connect(this, SIGNAL(test()), t, SLOT(throwException()));
    }

    void catchTest()
    {
        try
        {
            emit test(); // Will trigger Thrower::throwException().
        }
        catch (int number)
        {
            qDebug() << "Caught" << number;
        }
    }

signals:
    void test();
};

Unfortunately, it is not always possible to use this approach. For example, when you connect QPushButton::clicked() to Thrower::throwException(), clicking the button
will cause a crash of the event loop.

You could wrap QApplication::exec() in a try-block, but when you catch the exception, the GUI is most likely already destructed, so there is no real possibility to recover from an exception.

Also have a look at the Qt documention about exception safety.