Qt & qmqtt Client Library does not work with Windows - qt

Question

I have a problem using a library for a mqtt-client i got from GitHub (https://github.com/emqtt/qmqtt).
Im using Qt Creator 4.0.3 with Qt Version Qt 5.7.0 and compile with MinGW 5.3.0 on Windows 10.
I have already looked up some other answers on the Internet but they are mostly about compile or linking errors.
My problem is that the code is just not doing what it is supposed to (it does kind of nothing).
I'm already having problems with the example on the title screen (link above) which connects to a server/broker. It does simply nothing, i don't even get error messages or any other feedback.
My Code:
I have a Smartpointer to a Client Object
QScopedPointer<QMQTT::Client> client(new QMQTT::Client(QHostAddress("192.168.8.50"), 1883));
The Address and Port are correct, I already tested this with MQTTlens for Google Chrome.
Then I have a seperate class to handle my input and output (I use Multithreading). This class sends & receives signals so it can control the Client / give feedback to the user (through Console Output).
class MainIO : public QObject
{
Q_OBJECT
public:
explicit MainIO(QString clientId = "", QObject *parent = 0);
void mainMenue();
private:
QVector<QString> m_mainMenueStrings;
QString m_clientId;
signals:
void connectToHost();
void disconnectFromHost();
void subscribe(const QString &topic, const quint8 qos);
void unsubscribe(const QString &topic);
void publish(const QMQTT::Message &message);
public slots:
void onClientConnected();
void onClientDisconnected();
void onClientPublished();
void onClientError(const QMQTT::ClientError error);
void onClientReceived(const QMQTT::Message &message);
void add();
void subtract();
};
I move an object of the class to a thread in my main
QThread mainIOThread;
IoTClient::MainIO control(clientId);
control.moveToThread(&mainIOThread);
and then i connect the signals with slots before starting the thread
QObject::connect(&mainIOThread, &QThread::started
, &control, &IoTClient::MainIO::mainMenue);
/* Control -> Client */
QObject::connect(&control, &IoTClient::MainIO::connectToHost
, client.data(), &QMQTT::Client::connectToHost);
QObject::connect(&control, &IoTClient::MainIO::subscribe
, client.data(), &QMQTT::Client::subscribe);
QObject::connect(&control, &IoTClient::MainIO::unsubscribe
, client.data(), &QMQTT::Client::unsubscribe);
QObject::connect(&control, &IoTClient::MainIO::publish
, client.data(), &QMQTT::Client::publish);
/* Client -> Control */
QObject::connect(client.data(), &QMQTT::Client::connected
, &control, &IoTClient::MainIO::onClientConnected);
QObject::connect(client.data(), &QMQTT::Client::disconnected
, &control, &IoTClient::MainIO::onClientDisconnected);
QObject::connect(client.data(), &QMQTT::Client::error
, &control, &IoTClient::MainIO::onClientError);
QObject::connect(client.data(), &QMQTT::Client::published
, &control, &IoTClient::MainIO::onClientPublished);
QObject::connect(client.data(), &QMQTT::Client::received
, &control, &IoTClient::MainIO::onClientReceived);
mainIOThread.start();
The mainMenue-Method looks as follows:
void MainIO::mainMenue()
{
std::system("cls");
qDebug().noquote().nospace() << (tr("clients/") + m_clientId +
tr("/state"));
/* Print Menue */
qDebug().noquote().nospace() << "QMQTT-Client";
for (int i = 0; i < m_mainMenueStrings.size(); i++)
{
qDebug().noquote().nospace() << "\t(" << i+1 << ") " <<
m_mainMenueStrings[i];
}
qDebug().noquote().nospace() << "Ihre Auswahl: ";
/* select choice */
int option = -1;
while ((option >= m_mainMenueStrings.size()) || (option < 0)) {
std::cin >> option;
}
option--;
switch(option) {
case 0: emit this->connectToHost();
break;
case 1: add();
break;
case 2: subtract();
break;
case 3: emit this->disconnectFromHost();
break;
default:
qDebug().noquote().nospace() << "Fehlerhafte Eingabe";
}
}
The Console output looks kinda like following:
(1) connect
(2) add
...
your input:_
after I send some input (1 for connect) nothing happens. i dont get any error (i have connected the error signal from the client to a error slot) or other signals.
I have already tested this connection in the source code and can't come to a conclusion, because it just makes no sense (to me) that the client won't connect to the broker.
The code only fails with Windows, it does work with Linux.

Answer 1

I have solved this problem. It was, that the qmake version in the project did not work properly after deployment (on Windows).
I used the Qbs version, but this one could not be deployed. I built it and copied the generated files needed (.dll and so on) into the corresponding Qt directories on my machine.