bool is converted to another value in signal-slot mechanism?

user4592357

I have a class that emits a signal:

bool myClass::eventFilter(QObject *object, QEvent *event) {
    if(event->type() == QEvent::MouseButtonRelease) {
        auto o = static_cast<someClass *>(object);
        emit clicked(o->getName(), o->isValid())
        return true;
    }

    return QScrollArea::eventFilter(object, event);
}

clicked()'s declaration:

void clicked(const QString &name, bool isValid);

and I have another class where I do a connect:

QObject::connect(ob, SIGNAL(clicked(const QString &, bool)), SLOT(load(const QString &, bool)));

in load I print the passed values and I got 80 and 64 for bool:

void otherClass::load(const QString &name, bool isValid) {
    std::cout << name.toStdString() << ' ' <<  isValid << std::endl;
}

When I print the values from eventFilter(), I still get 80 for bool. However, if I print the value of isValid() from another place, I get correct 0 or 1.

Why is this? and how can I get correct bool values in my slot?

[Edit: fixed markup ~~ @Wieland]

? Offline

Hi! Please show us the declaration of someClass::isValid.

user4592357

@Wieland

is just returns a bool data member:

bool someClass::isValid() const {
    return m_isValid;
}

and m_isValid is set in the constructor

EDIT: this is weird. there's another thing that makes me bowl my eyes. getName() and isValid() are const member fucntions, and as i found out they are the reason the program works wrong, 80? what is 80? i tried to emit clicked(QString("1234"), false); and that time i get 0 printed correctly.

so what is the reason for this? can't i call something during emitting a signal???

SGaist

Hi,

One thing, you should use qobject_cast and not static_cast when dealing with QObject based classes.

Did you try to print what you emit before calling emit ?

user4592357

my bad... i hadn't installed the event filter on the watched object. everything works now.

@SGaist thanks for the advice. changed to qobject_cast. well at least i learned that from my stupid mistake

JonB

And always check the return of qobject_cast<> as per
https://forum.qt.io/topic/83689/setmodeldata-crashes-program/14 onward :)

user4592357

i know, i know! my app crashed too :( then i checked the return value and everything is okay now!

p.s. everyone should learn from their own pain (i mean the crash) ;)