Wsrtjtyk

This question is similar to one that has been asked before, but I am having an issue with Qt recognizing my class and functions despite them being defined. I am doing this in linux where the Qt version is only 5.5 while the windows version is at 5.11. When running the same program in windows, I get no errors.

I am getting "undefined reference to QCanBus::instance()" errors

This is happening for every QCanBus function. In my code snippet from connectdialogue.cpp, only the first occurrence is featured and can be found at the second to last code line and gives the errors:

"undefined reference to QCanBus::instance()"

"undefined reference to QCanBus::plugins()"

These errors are given despite being defined in the qcanbus.h headder file.

I have tried adding the lines static QCanBus *instance() or alternatively QCanBus *instance() under the #include lines in my connectdialogue.cpp, but I am then presented with the warning:
"QCanBus::instance() is defined, but unused" when it is clearly used on the second to last line of the featured code snippet.

How do I fix these errors?

connectdialogue.cpp

 #include "connectdialog.h"

 #include "ui_connectdialog.h"



 #include "qcanbus.h"



ConnectDialog::ConnectDialog(QWidget *parent) :

     QDialog(parent),

     m_ui(new Ui::ConnectDialog)

{

m_ui->setupUi(this);



m_ui->errorFilterEdit->setValidator(new QIntValidator(0, 0x1FFFFFFFU, this));



m_ui->loopbackBox->addItem(tr("unspecified"), QVariant());

m_ui->loopbackBox->addItem(tr("false"), QVariant(false));

m_ui->loopbackBox->addItem(tr("true"), QVariant(true));



m_ui->receiveOwnBox->addItem(tr("unspecified"), QVariant());

m_ui->receiveOwnBox->addItem(tr("false"), QVariant(false));

m_ui->receiveOwnBox->addItem(tr("true"), QVariant(true));



m_ui->canFdBox->addItem(tr("false"), QVariant(false));

m_ui->canFdBox->addItem(tr("true"), QVariant(true));



m_ui->dataBitrateBox->setFlexibleDateRateEnabled(true);



connect(m_ui->okButton, &QPushButton::clicked, this, &ConnectDialog::ok);

connect(m_ui->cancelButton, &QPushButton::clicked, this, &ConnectDialog::cancel);

connect(m_ui->useConfigurationBox, &QCheckBox::clicked,

        m_ui->configurationBox, &QGroupBox::setEnabled);

connect(m_ui->backendListBox, &QComboBox::currentTextChanged,

        this, &ConnectDialog::backendChanged);

connect(m_ui->interfaceListBox, &QComboBox::currentTextChanged,

        this, &ConnectDialog::interfaceChanged);

m_ui->rawFilterEdit->hide();

m_ui->rawFilterLabel->hide();



m_ui->backendListBox->addItems(QCanBus::instance()->plugins());



updateSettings();

 }

qcanbus.h

#ifndef QCANBUS_H

#define QCANBUS_H



#include <QtCore/qobject.h>

#include "qserialbusglobal.h"

#include "qcanbusdevice.h"

#include "qcanbusdeviceinfo.h"



QT_BEGIN_NAMESPACE



class Q_SERIALBUS_EXPORT QCanBus : public QObject

{

    Q_OBJECT



public:

    static QCanBus *instance();

    QStringList plugins() const;



    QList<QCanBusDeviceInfo> availableDevices(const QString &plugin, QString *errorMessage = nullptr) const;



    QCanBusDevice *createDevice(const QString &plugin,

                                const QString &interfaceName,

                                QString *errorMessage = nullptr) const;



private:

    QCanBus(QObject *parent = nullptr);



    Q_DISABLE_COPY(QCanBus)

};



QT_END_NAMESPACE



#endif // QSERIALBUS_H