Qt sends a signal to another thread

Question

I was looking for SO for this question, but they were slightly different from mine. My problem is that I do not want to receive a signal from another stream, but I want to send it. Getting work in my application, but when I try to send, I get an error that I try to send to another thread ... I do not know how to fix it. This is my situation: I have a Gui application. In the MainWindow class, I create a myThread object that is inherited from Qthread. Then I start a new thread. A signal exists in MainWindow, and a slot exists in myThread (this code runs in the main window). When I try to do:

connect(this, SIGNAL(disconnect(), connectionThread, SLOT(stop())); 

stop () is the slot in the connection stream, and disconnect () is the signal from MainWindow. When a signal is emitted, I get:

 ASSERT failure in QCoreApplication::sendEvent: "Cannot send events to objects owned by a different thread. Current thread 128f8250. Receiver '' (of type 'QNativeSocketEngine') was created in thread 14bae218", file kernel\qcoreapplication.cpp, line 521 Invalid parameter passed to C runtime function. Invalid parameter passed to C runtime function. 

Is there any way to overcome this? I need to be able to send and receive events through signals and slots in and out of the stream that I created. I would really seduce all the help!

PS: I tried the direct link.

 connect(this, SIGNAL(disconnectFromOven()), connectionThread, SLOT(stop()), Qt::DirectConnection); 

This is the code: Mainwindow.h:

 #ifndef MAINWINDOW_H #define MAINWINDOW_H #include <QMainWindow> namespace Ui { class MainWindow; } class MainWindow : public QMainWindow { Q_OBJECT public: explicit MainWindow(QWidget *parent = 0); ~MainWindow(); void moveUndoView(); signals: void disconnectFromOven(); }; #endif // MAINWINDOW_H 

mainwindow.cpp:

 #include "mainwindow.h" MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow) { ui->setupUi(this); initComponents(); QString ip = "10.10.10.17"; int port = 5432; connectionThread = new TcpThread(ip, port, connectAndStay); show(); // tcp connection connect(connectionThread, SIGNAL(connectionEstablished()), this, SLOT(on_connectionEstablished())); connect(connectionThread, SIGNAL(connectionNotEstablished()), this, SLOT(on_connectionNotEstablished())); connect(this, SIGNAL(disconnectFromOven()), connectionThread, SLOT(stop())); } void MainWindow::on_action_Disconnect_triggered() { emit disconnectFromOven(); } 

tcpthread.h:

 #ifndef TCPTHREAD_H #define TCPTHREAD_H #include <QThread> #include <QDebug> #include "tcpconnection.h" class TcpThread : public QThread { Q_OBJECT public: explicit TcpThread(QString& address, int& port, conType_t conType, QObject *parent = 0); void run(); // inherited signals: void connectionStatusOk(); void connectionEstablished(); void connectionNotEstablished(); private slots: void stop(); void connectionClosed(); void connectionOpened(); void connectionOpenFailed(); }; #endif // TCPTHREAD_H 

tcpthread.cpp:

 #include "tcpthread.h" TcpThread::TcpThread(QString& address, int& port, conType_t conType, QObject *parent) : QThread(parent) { this->address = address; this->port = port; this->conTypeRequested = conType; } void TcpThread::stop() { qDebug() << "Thread stop called, requesting disconnect"; tcpCon->doDisconnect(); } 

Answer 1

The QThread (connectionThread) instance lives in the thread that created it (main thread), and not in the thread that calls run (), so if you want to call slots, you need to use the first approach presented in the documentation here , look at the working approach -object.