Important: Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

use of deleted function 'Node::Node(const Node&)'



  • Hello!
    I've come across this bug. Usually it has to do with trying to make a copy of a QObject, and maybe the connect does that, but I'm not sure...
    I've cut down the code as much as possible so it still replicates the error

    //net.h
    
    #ifndef NET_H
    #define NET_H
    
    #include <QObject>
    #include "node.h"
    
    class Net : public QObject
    {
        Q_OBJECT
    public:
        explicit Net(QObject *parent = nullptr);
        void foo();
    
    signals:
        QString requestNodeInfo();
    
    private:
        QVector<Node> node;
    };
    
    #endif // NET_H
    
    //node.h
    
    #ifndef NODE_H
    #define NODE_H
    
    #include <QObject>
    
    class Net;
    
    class Node : public QObject
    {
        Q_OBJECT
    
    public:
        explicit Node(Net *parentNet = nullptr);
    
    public slots:
        QString provideNodeInfo();
    };
    
    #endif // NODE_H
    
    
    //main.cpp
    
    #include <QCoreApplication>
    
    int main(int argc, char *argv[])
    {
        QCoreApplication a(argc, argv);
    
        return a.exec();
    }
    
    
    //net.cpp
    
    #include "net.h"
    
    Net::Net(QObject *parent) : QObject(parent)
    {
    
    }
    
    void Net::foo()
    {
        for (int i=0; i<node.size(); i++)
        {
        connect(this,&Net::requestNodeInfo,&node[i],&Node::provideNodeInfo);
        }
    }
    
    
    //node.cpp
    
    #include "node.h"
    #include "net.h"
    
    Node::Node(Net *parentNet) : QObject(parentNet)
    {
    
    }
    
    QString Node::provideNodeInfo()
    {
    
    }
    
    
    

    The error messages are:
    use of deleted function 'Node::Node(const Node&)'
    'QObject::QObject(const &QObject) is private within this context


  • Lifetime Qt Champion

    Hi and welcome to the forums :)

    if this line is correct
    QVector<Node> node;
    that is the reason.
    It has to be
    QVector<Node *> node;
    or else it will try to copy the Node into the list. (which is not allowed)
    So the template type must be * (pointer to Node)


  • Lifetime Qt Champion

    Hi and welcome to the forums :)

    if this line is correct
    QVector<Node> node;
    that is the reason.
    It has to be
    QVector<Node *> node;
    or else it will try to copy the Node into the list. (which is not allowed)
    So the template type must be * (pointer to Node)



  • Thank you, had a blind spot there haha!


  • Lifetime Qt Champion

    @fT3g0
    :) we all know such situations.


Log in to reply