Ошибка no matching member function for call to connect

I’m writing a program that send an UDP frame every 10 mS. Here’s how my program is supposed to work :

I’ve got a client class :

//Constructor
clientSupervision::clientSupervision()
{
}

void clientSupervision::sendDataUDP(){
    //Create a frame and send it
...
}

void clientSupervision::sendDataUDPTimer(int timer){
    QTimer *tempsEnvoieTrameSupervision = new QTimer();//Create a timer
    tempsEnvoieTrameSupervision->setInterval(timer);//Set the interval

    //Mise en place des connections
    QObject::connect (tempsEnvoieTrameSupervision,SIGNAL (timeout()),this, SLOT (envoiTrameSupervision())); //Connect the timer to the function
    tempsEnvoieTrameSupervision->start();// Start the timer
}

//Call sendDataUDP
void clientSupervision::envoiTrameSupervision(){
    std::cout << "Envoi de la trame de supervision";
    sendDataUDP();
}

My header file of clienSupervision.h :

#ifndef CLIENTSUPERVISION_H
#define CLIENTSUPERVISION_H
#include <winsock2.h> // pour les fonctions socket
#include <cstdio> // Pour les Sprintf
#include "StructureSupervision.h"
#include "utilitaireudp.h"
#include <QTimer>
#include <QObject>
#include <iostream>
class clientSupervision
{
    Q_OBJECT
public:
    clientSupervision();
    void sendDataUDP();
    void sendDataUDPTimer(int timer);

public slots:
    void envoiTrameSupervision();
};

#endif // CLIENTSUPERVISION_H

Then I use this in my main :

int main(int argc, char *argv[])
{
    clientSupervision c;
    c.sendDataUDPTimer(10);
    QCoreApplication a(argc, argv);

    return a.exec();
}

I’ve got the error :

no matching function for call to ‘QObject::connect(QTimer*&, const char*, clientSupervision* const, const char*)

I don’t understand why the connect function can’t find a matching function.

What should I change?

Hi,

I made a very simple test project, just a QMainWindow. I instantiated a QSpinBox in the constructor and tried to connect it to a public slot of MainWindow. Yet I get the error «no matching member function for call to ‘connect’. This using both the old and new style connect syntax. My header includes Q_OBJECT. Both QMainWindow and QSpinBox derive from QObject.

I must be missing/forgetting something very simple here. Why on earth doesn’t this work?

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 = nullptr);
    ~MainWindow();

public slots:
    void doTest(int val);

private:
    Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H

mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"

#include <QSpinBox>

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    QSpinBox* oSpinBox = new QSpinBox(this);
    connect(oSpinBox, &QSpinBox::valueChanged, this, &MainWindow::doTest);

}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::doTest(int val)
{
    // do something
}

I’m trying to port one of my programs from Python to C++, but I can’t figure out some simple Qt stuff.

In my mainwindow header, I’ve got:

#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();

public slots:
    void recordButton_slot();

private:
    Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H

and in my mainwindow.cpp, I’ve got:

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    // Connect signals/slots
    connect(ui->recordButton, SIGNAL( clicked()) ), this, SLOT(record_button_slot());
}

MainWindow::~MainWindow()
{
    delete ui;
}

When I try to compile, I get

no matching member function for call to 'connect'

If I comment out the line

connect(ui->recordButton, SIGNAL( clicked()) ), this, SLOT(record_button_slot());

the code compiles. I’ve tried using QObject::connect, but that doesn’t seem to affect anything.

Do you see where I went wrong? I’ve found quite a few similar questions but I don’t quite understand how to fix this.

MyThread наследует QThread, w.getScene() возвращает указатель на объект класса Scene, унаследованный от QGraphicsScene

Создаю в main’e 2 коннекта:

Получаю для каждого из коннектов

error: no matching function for call to ‘QObject::connect(MyThread*, const char*, Scene*, const char*)’
note: candidates are: static bool QObject::connect(const QObject*, const char*, const QObject*, const char*, Qt::ConnectionType)
note:                 bool QObject::connect(const QObject*, const char*, const char*, Qt::ConnectionType) const

в чём дело?