QML call function in C++ with threads

jeremy_k

@jsulm Pulling code from moc output I happen to have lying around:

For a signal void stuffChanged(QString), moc generates:

// SIGNAL 0
void Singleton::stuffChanged(QString _t1)
{
    void *_a[] = { Q_NULLPTR, const_cast<void*>(reinterpret_cast<const void*>(&_t1)) };
    QMetaObject::activate(this, &staticMetaObject, 0, _a);
}

QMetaObject::activate() is a private API in qtbase/src/corelib/kernel/qobject.cpp. The version that takes a pointer to the static meta object eventually calls this one:

void QMetaObject::activate(QObject *sender, int signalOffset, int local_signal_index, void **argv)
{
 ...
        if ((c->connectionType == Qt::AutoConnection && !receiverInSameThread)
                || (c->connectionType == Qt::QueuedConnection)) {
                queued_activate(sender, signal_index, c, argv ? argv : empty_argv, locker);
                continue;
...
}

The full source is a little lengthy to quote here, but check it out if you're curious. Also, you can trace the emission of a signal through to the call of a slot for an object in the same thread without a return to the event loop with the debugger.

To reiterate, signal emission is done when emit signal() returns. Calling of a particular slot may be pending for any queued connection.

Cleiton Bueno

I agree, this while() was bothering me.

I'm using a _timer with QTimer where start() by clicking, I get the Socket data with onReadyRead() process met _timer.stop() but emito sign for the status, seems to be working well.

But I accept suggestions for improvement, but I removed the loop while()