Cleanup and modernize the Modbus examples

* Replace static_cast with QOverload
* Fix some Clang warnings
* Mark user-visible strings with tr()
* Disable verbose log output
* Replace auto-connect with explicit
  functor-style connect
* Initialize members at declaration
* Small style cleanup

Change-Id: Idcb6c24a8733e7fd659ad4750ce0798a72c84af6
Reviewed-by: Alex Blasche <alexander.blasche@qt.io>

15 files changed, 162 insertions, 135 deletions

diff --git a/examples/serialbus/modbus/adueditor/adueditor.pro b/examples/serialbus/modbus/adueditor/adueditor.pro
index facba76..77a6158 100644
--- a/examples/serialbus/modbus/adueditor/adueditor.pro
+++ b/examples/serialbus/modbus/adueditor/adueditor.pro
@@ -7,9 +7,19 @@ QT += serialbus-private core-private
 requires(qtConfig(combobox))
 requires(qtConfig(modbus-serialport))
 
-FORMS += interface.ui
-SOURCES += main.cpp mainwindow.cpp modbustcpclient.cpp
-HEADERS += mainwindow.h plaintextedit.h modbustcpclient.h modbustcpclient_p.h
+SOURCES += \
+    main.cpp \
+    mainwindow.cpp \
+    modbustcpclient.cpp
+
+HEADERS += \
+    mainwindow.h  \
+    modbustcpclient.h \
+    modbustcpclient_p.h \
+    plaintextedit.h
+
+FORMS += \
+    interface.ui
 
 target.path = $$[QT_INSTALL_EXAMPLES]/serialbus/modbus/adueditor
 INSTALLS += target
diff --git a/examples/serialbus/modbus/adueditor/mainwindow.cpp b/examples/serialbus/modbus/adueditor/mainwindow.cpp
index 862be6a..995cfc9 100644
--- a/examples/serialbus/modbus/adueditor/mainwindow.cpp
+++ b/examples/serialbus/modbus/adueditor/mainwindow.cpp
@@ -52,8 +52,8 @@
 #include "modbustcpclient.h"
 
 #include <QLoggingCategory>
-#include <QModbusRtuSerialMaster>
 #include <QModbusPdu>
+#include <QModbusRtuSerialMaster>
 #include <QSerialPortInfo>
 
 #ifndef QT_STATIC
@@ -84,7 +84,7 @@ MainWindow::MainWindow(QWidget *parent)
     for (const QSerialPortInfo &info : ports)
         serialPortCombo->addItem(info.portName(), false);
     serialPortCombo->insertSeparator(serialPortCombo->count());
-    serialPortCombo->addItem(QStringLiteral("Add port..."), true);
+    serialPortCombo->addItem(tr("Add port..."), true);
     serialPortCombo->setInsertPolicy(QComboBox::InsertAtTop);
 
     connect(tcpRadio, &QRadioButton::toggled, this, [this](bool toggled) {
@@ -119,14 +119,14 @@ void MainWindow::on_sendButton_clicked()
         return;
     }
 
-    const quint8 address = (isSerial ? addressSpin : ui1Spin)->value();
+    const quint8 address = quint8((isSerial ? addressSpin : ui1Spin)->value());
     if (isCustom) {
         qDebug() << "Send: Sending custom PDU.";
         reply = m_device->sendRawRequest(QModbusRequest(QModbusRequest::FunctionCode(
             pduData[0]), pduData.mid(1)), address);
     } else {
         qDebug() << "Send: Sending PDU with predefined function code.";
-        quint16 fc = (isSerial ? fcSerialDrop : fcTcpDrop)->currentText().left(4).toShort(0, 16);
+        quint16 fc = (isSerial ? fcSerialDrop : fcTcpDrop)->currentText().left(4).toUShort(0, 16);
         reply = m_device->sendRawRequest(QModbusRequest(QModbusRequest::FunctionCode(fc), pduData),
             address);
     }
@@ -149,24 +149,23 @@ void MainWindow::on_connectButton_clicked()
 {
     if (tcpRadio->isChecked()) {
         auto device = new ModbusTcpClient;
-        using signature = void (QSpinBox::*)(int);
-        connect(ti1Spin, static_cast<signature>(&QSpinBox::valueChanged), device,
-            &ModbusTcpClient::valueChanged);
-        connect(ti2Spin, static_cast<signature>(&QSpinBox::valueChanged), device,
-            &ModbusTcpClient::valueChanged);
-
-        connect(pi1Spin, static_cast<signature>(&QSpinBox::valueChanged), device,
-            &ModbusTcpClient::valueChanged);
-        connect(pi2Spin, static_cast<signature>(&QSpinBox::valueChanged), device,
-            &ModbusTcpClient::valueChanged);
-
-        connect(l1Spin, static_cast<signature>(&QSpinBox::valueChanged), device,
-            &ModbusTcpClient::valueChanged);
-        connect(l2Spin, static_cast<signature>(&QSpinBox::valueChanged), device,
-            &ModbusTcpClient::valueChanged);
-
-        connect(ui1Spin, static_cast<signature>(&QSpinBox::valueChanged), device,
-            &ModbusTcpClient::valueChanged);
+        connect(ti1Spin, QOverload<int>::of(&QSpinBox::valueChanged),
+                device, &ModbusTcpClient::valueChanged);
+        connect(ti2Spin, QOverload<int>::of(&QSpinBox::valueChanged),
+                device, &ModbusTcpClient::valueChanged);
+
+        connect(pi1Spin, QOverload<int>::of(&QSpinBox::valueChanged),
+                device, &ModbusTcpClient::valueChanged);
+        connect(pi2Spin, QOverload<int>::of(&QSpinBox::valueChanged),
+                device, &ModbusTcpClient::valueChanged);
+
+        connect(l1Spin, QOverload<int>::of(&QSpinBox::valueChanged),
+                device, &ModbusTcpClient::valueChanged);
+        connect(l2Spin, QOverload<int>::of(&QSpinBox::valueChanged),
+                device, &ModbusTcpClient::valueChanged);
+
+        connect(ui1Spin, QOverload<int>::of(&QSpinBox::valueChanged),
+                device, &ModbusTcpClient::valueChanged);
 
         m_device = device;
         device->valueChanged(0);    // trigger update
diff --git a/examples/serialbus/modbus/adueditor/modbustcpclient_p.h b/examples/serialbus/modbus/adueditor/modbustcpclient_p.h
index 9d091d8..a563b6f 100644
--- a/examples/serialbus/modbus/adueditor/modbustcpclient_p.h
+++ b/examples/serialbus/modbus/adueditor/modbustcpclient_p.h
@@ -73,7 +73,7 @@ public:
             QDataStream output(&buffer, QIODevice::WriteOnly);
             output << m_tId << m_pId << m_length << m_uId << request;
 
-            int writtenBytes = m_socket->write(buffer);
+            qint64 writtenBytes = m_socket->write(buffer);
             if (writtenBytes == -1 || writtenBytes < buffer.size()) {
                 Q_Q(ModbusTcpClient);
                 qDebug() << "Cannot write request to socket.";
@@ -91,14 +91,13 @@ public:
 
         Q_Q(ModbusTcpClient);
         auto reply = new QModbusReply(type, m_uId, q);
-        const auto element = QueueElement{ reply, request, unit, m_numberOfRetries,
-            m_responseTimeoutDuration };
+        const auto element = QueueElement{reply, request, unit, m_numberOfRetries,
+            m_responseTimeoutDuration};
         m_transactionStore.insert(m_tId, element);
 
-        using TypeId = void (QTimer::*)(int);
         q->connect(q, &QModbusClient::timeoutChanged,
-                   element.timer.data(), static_cast<TypeId>(&QTimer::setInterval));
-        QObject::connect(element.timer.data(), &QTimer::timeout, [this, writeToSocket]() {
+                   element.timer.data(), QOverload<int>::of(&QTimer::setInterval));
+        q->connect(element.timer.data(), &QTimer::timeout, [this, writeToSocket]() {
             if (!m_transactionStore.contains(m_tId))
                 return;
 
@@ -120,13 +119,13 @@ public:
             }
         });
         element.timer->start();
-    return reply;
+        return reply;
     }
 
-    quint16 m_tId;
-    quint16 m_pId;
-    quint16 m_length;
-    quint8 m_uId;
+    quint16 m_tId = 0;
+    quint16 m_pId = 0;
+    quint16 m_length = 0;
+    quint8 m_uId = 0;
 };
 
 #endif // MODBUSTCPCLIENT_P_H
diff --git a/examples/serialbus/modbus/adueditor/plaintextedit.h b/examples/serialbus/modbus/adueditor/plaintextedit.h
index 3cbbaaf..cbc590c 100644
--- a/examples/serialbus/modbus/adueditor/plaintextedit.h
+++ b/examples/serialbus/modbus/adueditor/plaintextedit.h
@@ -81,12 +81,12 @@ public:
     void contextMenuEvent(QContextMenuEvent *event)
     {
         QMenu menu(this);
-        menu.addAction(QStringLiteral("Clear"), this, &QPlainTextEdit::clear);
+        menu.addAction(tr("Clear"), this, &QPlainTextEdit::clear);
 #ifndef QT_NO_CLIPBOARD
-        menu.addAction(QStringLiteral("Copy"), this, &QPlainTextEdit::copy, QKeySequence::Copy);
+        menu.addAction(tr("Copy"), this, &QPlainTextEdit::copy, QKeySequence::Copy);
 #endif
         menu.addSeparator();
-        menu.addAction(QStringLiteral("Select All"), this, &QPlainTextEdit::selectAll,
+        menu.addAction(tr("Select All"), this, &QPlainTextEdit::selectAll,
             QKeySequence::SelectAll);
         menu.exec(event->globalPos());
     }
diff --git a/examples/serialbus/modbus/master/main.cpp b/examples/serialbus/modbus/master/main.cpp
index 4f97a39..19a1d5b 100644
--- a/examples/serialbus/modbus/master/main.cpp
+++ b/examples/serialbus/modbus/master/main.cpp
@@ -55,9 +55,8 @@
 
 int main(int argc, char *argv[])
 {
-    // TODO uncomment this line before release
-    // right now we always need it
-    QLoggingCategory::setFilterRules(QStringLiteral("qt.modbus* = true"));
+    // Uncomment the following line to enable logging
+    // QLoggingCategory::setFilterRules(QStringLiteral("qt.modbus* = true"));
     QApplication a(argc, argv);
     MainWindow w;
     w.show();
diff --git a/examples/serialbus/modbus/master/mainwindow.cpp b/examples/serialbus/modbus/master/mainwindow.cpp
index 6600af8..7427a17 100644
--- a/examples/serialbus/modbus/master/mainwindow.cpp
+++ b/examples/serialbus/modbus/master/mainwindow.cpp
@@ -67,8 +67,6 @@ enum ModbusConnection {
 MainWindow::MainWindow(QWidget *parent)
     : QMainWindow(parent)
     , ui(new Ui::MainWindow)
-    , lastRequest(nullptr)
-    , modbusDevice(nullptr)
 {
     ui->setupUi(this);
 
@@ -82,8 +80,8 @@ MainWindow::MainWindow(QWidget *parent)
 
     ui->writeValueTable->setModel(writeModel);
     ui->writeValueTable->hideColumn(2);
-    connect(writeModel, &WriteRegisterModel::updateViewport, ui->writeValueTable->viewport(),
-        static_cast<void (QWidget::*)()>(&QWidget::update));
+    connect(writeModel, &WriteRegisterModel::updateViewport,
+            ui->writeValueTable->viewport(), QOverload<>::of(&QWidget::update));
 
     ui->writeTable->addItem(tr("Coils"), QModbusDataUnit::Coils);
     ui->writeTable->addItem(tr("Discrete Inputs"), QModbusDataUnit::DiscreteInputs);
@@ -92,11 +90,11 @@ MainWindow::MainWindow(QWidget *parent)
 
 #if QT_CONFIG(modbus_serialport)
     ui->connectType->setCurrentIndex(0);
-    on_connectType_currentIndexChanged(0);
+    onConnectTypeChanged(0);
 #else
     // lock out the serial port option
     ui->connectType->setCurrentIndex(1);
-    on_connectType_currentIndexChanged(1);
+    onConnectTypeChanged(1);
     ui->connectType->setEnabled(false);
 #endif
 
@@ -105,10 +103,10 @@ MainWindow::MainWindow(QWidget *parent)
         model->setItem(i, new QStandardItem(QStringLiteral("%1").arg(i + 1)));
     ui->writeSize->setModel(model);
     ui->writeSize->setCurrentText("10");
-    connect(ui->writeSize,&QComboBox::currentTextChanged, writeModel,
-        &WriteRegisterModel::setNumberOfValues);
+    connect(ui->writeSize, &QComboBox::currentTextChanged,
+            writeModel, &WriteRegisterModel::setNumberOfValues);
 
-    auto valueChanged = static_cast<void (QSpinBox::*)(int)> (&QSpinBox::valueChanged);
+    auto valueChanged = QOverload<int>::of(&QSpinBox::valueChanged);
     connect(ui->writeAddress, valueChanged, writeModel, &WriteRegisterModel::setStartAddress);
     connect(ui->writeAddress, valueChanged, this, [this, model](int i) {
         int lastPossibleIndex = 0;
@@ -142,16 +140,28 @@ void MainWindow::initActions()
     ui->actionExit->setEnabled(true);
     ui->actionOptions->setEnabled(true);
 
+    connect(ui->connectButton, &QPushButton::clicked,
+            this, &MainWindow::onConnectButtonClicked);
     connect(ui->actionConnect, &QAction::triggered,
-            this, &MainWindow::on_connectButton_clicked);
+            this, &MainWindow::onConnectButtonClicked);
     connect(ui->actionDisconnect, &QAction::triggered,
-            this, &MainWindow::on_connectButton_clicked);
+            this, &MainWindow::onConnectButtonClicked);
+    connect(ui->readButton, &QPushButton::clicked,
+            this, &MainWindow::onReadButtonClicked);
+    connect(ui->writeButton, &QPushButton::clicked,
+            this, &MainWindow::onWriteButtonClicked);
+    connect(ui->readWriteButton, &QPushButton::clicked,
+            this, &MainWindow::onReadWriteButtonClicked);
+    connect(ui->connectType, QOverload<int>::of(&QComboBox::currentIndexChanged),
+            this, &MainWindow::onConnectTypeChanged);
+    connect(ui->writeTable, QOverload<int>::of(&QComboBox::currentIndexChanged),
+            this, &MainWindow::onWriteTableChanged);
 
     connect(ui->actionExit, &QAction::triggered, this, &QMainWindow::close);
     connect(ui->actionOptions, &QAction::triggered, m_settingsDialog, &QDialog::show);
 }
 
-void MainWindow::on_connectType_currentIndexChanged(int index)
+void MainWindow::onConnectTypeChanged(int index)
 {
     if (modbusDevice) {
         modbusDevice->disconnectDevice();
@@ -159,7 +169,7 @@ void MainWindow::on_connectType_currentIndexChanged(int index)
         modbusDevice = nullptr;
     }
 
-    auto type = static_cast<ModbusConnection> (index);
+    auto type = static_cast<ModbusConnection>(index);
     if (type == Serial) {
 #if QT_CONFIG(modbus_serialport)
         modbusDevice = new QModbusRtuSerialMaster(this);
@@ -182,18 +192,18 @@ void MainWindow::on_connectType_currentIndexChanged(int index)
             statusBar()->showMessage(tr("Could not create Modbus client."), 5000);
     } else {
         connect(modbusDevice, &QModbusClient::stateChanged,
-                this, &MainWindow::onStateChanged);
+                this, &MainWindow::onModbusStateChanged);
     }
 }
 
-void MainWindow::on_connectButton_clicked()
+void MainWindow::onConnectButtonClicked()
 {
     if (!modbusDevice)
         return;
 
     statusBar()->clearMessage();
     if (modbusDevice->state() != QModbusDevice::ConnectedState) {
-        if (static_cast<ModbusConnection> (ui->connectType->currentIndex()) == Serial) {
+        if (static_cast<ModbusConnection>(ui->connectType->currentIndex()) == Serial) {
             modbusDevice->setConnectionParameter(QModbusDevice::SerialPortNameParameter,
                 ui->portEdit->text());
 #if QT_CONFIG(modbus_serialport)
@@ -226,7 +236,7 @@ void MainWindow::on_connectButton_clicked()
     }
 }
 
-void MainWindow::onStateChanged(int state)
+void MainWindow::onModbusStateChanged(int state)
 {
     bool connected = (state != QModbusDevice::UnconnectedState);
     ui->actionConnect->setEnabled(!connected);
@@ -238,7 +248,7 @@ void MainWindow::onStateChanged(int state)
         ui->connectButton->setText(tr("Disconnect"));
 }
 
-void MainWindow::on_readButton_clicked()
+void MainWindow::onReadButtonClicked()
 {
     if (!modbusDevice)
         return;
@@ -247,7 +257,7 @@ void MainWindow::on_readButton_clicked()
 
     if (auto *reply = modbusDevice->sendReadRequest(readRequest(), ui->serverEdit->value())) {
         if (!reply->isFinished())
-            connect(reply, &QModbusReply::finished, this, &MainWindow::readReady);
+            connect(reply, &QModbusReply::finished, this, &MainWindow::onReadReady);
         else
             delete reply; // broadcast replies return immediately
     } else {
@@ -255,7 +265,7 @@ void MainWindow::on_readButton_clicked()
     }
 }
 
-void MainWindow::readReady()
+void MainWindow::onReadReady()
 {
     auto reply = qobject_cast<QModbusReply *>(sender());
     if (!reply)
@@ -263,7 +273,7 @@ void MainWindow::readReady()
 
     if (reply->error() == QModbusDevice::NoError) {
         const QModbusDataUnit unit = reply->result();
-        for (uint i = 0; i < unit.valueCount(); i++) {
+        for (int i = 0, total = int(unit.valueCount()); i < total; ++i) {
             const QString entry = tr("Address: %1, Value: %2").arg(unit.startAddress() + i)
                                      .arg(QString::number(unit.value(i),
                                           unit.registerType() <= QModbusDataUnit::Coils ? 10 : 16));
@@ -282,7 +292,7 @@ void MainWindow::readReady()
     reply->deleteLater();
 }
 
-void MainWindow::on_writeButton_clicked()
+void MainWindow::onWriteButtonClicked()
 {
     if (!modbusDevice)
         return;
@@ -290,7 +300,7 @@ void MainWindow::on_writeButton_clicked()
 
     QModbusDataUnit writeUnit = writeRequest();
     QModbusDataUnit::RegisterType table = writeUnit.registerType();
-    for (uint i = 0; i < writeUnit.valueCount(); i++) {
+    for (int i = 0, total = int(writeUnit.valueCount()); i < total; ++i) {
         if (table == QModbusDataUnit::Coils)
             writeUnit.setValue(i, writeModel->m_coils[i + writeUnit.startAddress()]);
         else
@@ -319,7 +329,7 @@ void MainWindow::on_writeButton_clicked()
     }
 }
 
-void MainWindow::on_readWriteButton_clicked()
+void MainWindow::onReadWriteButtonClicked()
 {
     if (!modbusDevice)
         return;
@@ -328,7 +338,7 @@ void MainWindow::on_readWriteButton_clicked()
 
     QModbusDataUnit writeUnit = writeRequest();
     QModbusDataUnit::RegisterType table = writeUnit.registerType();
-    for (uint i = 0; i < writeUnit.valueCount(); i++) {
+    for (int i = 0, total = int(writeUnit.valueCount()); i < total; ++i) {
         if (table == QModbusDataUnit::Coils)
             writeUnit.setValue(i, writeModel->m_coils[i + writeUnit.startAddress()]);
         else
@@ -338,7 +348,7 @@ void MainWindow::on_readWriteButton_clicked()
     if (auto *reply = modbusDevice->sendReadWriteRequest(readRequest(), writeUnit,
         ui->serverEdit->value())) {
         if (!reply->isFinished())
-            connect(reply, &QModbusReply::finished, this, &MainWindow::readReady);
+            connect(reply, &QModbusReply::finished, this, &MainWindow::onReadReady);
         else
             delete reply; // broadcast replies return immediately
     } else {
@@ -346,7 +356,7 @@ void MainWindow::on_readWriteButton_clicked()
     }
 }
 
-void MainWindow::on_writeTable_currentIndexChanged(int index)
+void MainWindow::onWriteTableChanged(int index)
 {
     const bool coilsOrHolding = index == 0 || index == 3;
     if (coilsOrHolding) {
@@ -363,25 +373,25 @@ void MainWindow::on_writeTable_currentIndexChanged(int index)
 QModbusDataUnit MainWindow::readRequest() const
 {
     const auto table =
-        static_cast<QModbusDataUnit::RegisterType> (ui->writeTable->currentData().toInt());
+        static_cast<QModbusDataUnit::RegisterType>(ui->writeTable->currentData().toInt());
 
     int startAddress = ui->readAddress->value();
     Q_ASSERT(startAddress >= 0 && startAddress < 10);
 
     // do not go beyond 10 entries
-    int numberOfEntries = qMin(ui->readSize->currentText().toInt(), 10 - startAddress);
+    quint16 numberOfEntries = qMin(ui->readSize->currentText().toUShort(), quint16(10 - startAddress));
     return QModbusDataUnit(table, startAddress, numberOfEntries);
 }
 
 QModbusDataUnit MainWindow::writeRequest() const
 {
     const auto table =
-        static_cast<QModbusDataUnit::RegisterType> (ui->writeTable->currentData().toInt());
+        static_cast<QModbusDataUnit::RegisterType>(ui->writeTable->currentData().toInt());
 
     int startAddress = ui->writeAddress->value();
     Q_ASSERT(startAddress >= 0 && startAddress < 10);
 
     // do not go beyond 10 entries
-    int numberOfEntries = qMin(ui->writeSize->currentText().toInt(), 10 - startAddress);
+    quint16 numberOfEntries = qMin(ui->writeSize->currentText().toUShort(), quint16(10 - startAddress));
     return QModbusDataUnit(table, startAddress, numberOfEntries);
 }
diff --git a/examples/serialbus/modbus/master/mainwindow.h b/examples/serialbus/modbus/master/mainwindow.h
index d4d5036..186d004 100644
--- a/examples/serialbus/modbus/master/mainwindow.h
+++ b/examples/serialbus/modbus/master/mainwindow.h
@@ -83,24 +83,24 @@ private:
     QModbusDataUnit writeRequest() const;
 
 private slots:
-    void on_connectButton_clicked();
-    void onStateChanged(int state);
+    void onConnectButtonClicked();
+    void onModbusStateChanged(int state);
 
-    void on_readButton_clicked();
-    void readReady();
+    void onReadButtonClicked();
+    void onReadReady();
 
-    void on_writeButton_clicked();
-    void on_readWriteButton_clicked();
+    void onWriteButtonClicked();
+    void onReadWriteButtonClicked();
 
-    void on_connectType_currentIndexChanged(int);
-    void on_writeTable_currentIndexChanged(int);
+    void onConnectTypeChanged(int);
+    void onWriteTableChanged(int);
 
 private:
-    Ui::MainWindow *ui;
-    QModbusReply *lastRequest;
-    QModbusClient *modbusDevice;
-    SettingsDialog *m_settingsDialog;
-    WriteRegisterModel *writeModel;
+    Ui::MainWindow *ui = nullptr;
+    QModbusReply *lastRequest = nullptr;
+    QModbusClient *modbusDevice = nullptr;
+    SettingsDialog *m_settingsDialog = nullptr;
+    WriteRegisterModel *writeModel = nullptr;
 };
 
 #endif // MAINWINDOW_H
diff --git a/examples/serialbus/modbus/master/master.pro b/examples/serialbus/modbus/master/master.pro
index 188fbc1..d7a4885 100644
--- a/examples/serialbus/modbus/master/master.pro
+++ b/examples/serialbus/modbus/master/master.pro
@@ -7,17 +7,20 @@ TARGET = modbusmaster
 TEMPLATE = app
 CONFIG += c++11
 
-SOURCES += main.cpp\
-        mainwindow.cpp \
-        settingsdialog.cpp \
-        writeregistermodel.cpp
+SOURCES += \
+    main.cpp\
+    mainwindow.cpp \
+    settingsdialog.cpp \
+    writeregistermodel.cpp
 
-HEADERS  += mainwindow.h \
-         settingsdialog.h \
-        writeregistermodel.h
+HEADERS += \
+    mainwindow.h \
+    settingsdialog.h \
+    writeregistermodel.h
 
-FORMS    += mainwindow.ui \
-         settingsdialog.ui
+FORMS += \
+    mainwindow.ui \
+    settingsdialog.ui
 
 RESOURCES += \
     master.qrc
diff --git a/examples/serialbus/modbus/master/settingsdialog.h b/examples/serialbus/modbus/master/settingsdialog.h
index 98ba946..fbeb97a 100644
--- a/examples/serialbus/modbus/master/settingsdialog.h
+++ b/examples/serialbus/modbus/master/settingsdialog.h
@@ -88,7 +88,7 @@ public:
 
 private:
     Settings m_settings;
-    Ui::SettingsDialog *ui;
+    Ui::SettingsDialog *ui = nullptr;
 };
 
 #endif // SETTINGSDIALOG_H
diff --git a/examples/serialbus/modbus/master/writeregistermodel.cpp b/examples/serialbus/modbus/master/writeregistermodel.cpp
index 4b61e99..441f643 100644
--- a/examples/serialbus/modbus/master/writeregistermodel.cpp
+++ b/examples/serialbus/modbus/master/writeregistermodel.cpp
@@ -82,7 +82,7 @@ QVariant WriteRegisterModel::data(const QModelIndex &index, int role) const
     if (index.column() == CoilsColumn && role == Qt::CheckStateRole) // coils
         return m_coils.at(index.row()) ? Qt::Checked : Qt::Unchecked;
 
-    else if (index.column() == HoldingColumn && role == Qt::DisplayRole) //holding registers
+    if (index.column() == HoldingColumn && role == Qt::DisplayRole) // holding registers
         return QString("0x%1").arg(QString::number(m_holdingRegisters.at(index.row()), 16));
 
     return QVariant();
@@ -146,9 +146,9 @@ Qt::ItemFlags WriteRegisterModel::flags(const QModelIndex &index) const
     if ((index.row() < m_address) || (index.row() >= (m_address + m_number)))
         flags &= ~Qt::ItemIsEnabled;
 
-    if (index.column() == CoilsColumn) //coils
+    if (index.column() == CoilsColumn) // coils
         return flags | Qt::ItemIsUserCheckable;
-    if (index.column() == HoldingColumn) //holding registers
+    if (index.column() == HoldingColumn) // holding registers
         return flags | Qt::ItemIsEditable;
 
     return flags;
diff --git a/examples/serialbus/modbus/master/writeregistermodel.h b/examples/serialbus/modbus/master/writeregistermodel.h
index fe49591..4b0311e 100644
--- a/examples/serialbus/modbus/master/writeregistermodel.h
+++ b/examples/serialbus/modbus/master/writeregistermodel.h
@@ -79,8 +79,8 @@ signals:
     void updateViewport();
 
 public:
-    int m_number;
-    int m_address;
+    int m_number = 0;
+    int m_address = 0;
     QBitArray m_coils;
     QVector<quint16> m_holdingRegisters;
 };
diff --git a/examples/serialbus/modbus/slave/main.cpp b/examples/serialbus/modbus/slave/main.cpp
index 4f97a39..19a1d5b 100644
--- a/examples/serialbus/modbus/slave/main.cpp
+++ b/examples/serialbus/modbus/slave/main.cpp
@@ -55,9 +55,8 @@
 
 int main(int argc, char *argv[])
 {
-    // TODO uncomment this line before release
-    // right now we always need it
-    QLoggingCategory::setFilterRules(QStringLiteral("qt.modbus* = true"));
+    // Uncomment the following line to enable logging
+    // QLoggingCategory::setFilterRules(QStringLiteral("qt.modbus* = true"));
     QApplication a(argc, argv);
     MainWindow w;
     w.show();
diff --git a/examples/serialbus/modbus/slave/mainwindow.cpp b/examples/serialbus/modbus/slave/mainwindow.cpp
index 4a4c194..dc31196 100644
--- a/examples/serialbus/modbus/slave/mainwindow.cpp
+++ b/examples/serialbus/modbus/slave/mainwindow.cpp
@@ -67,18 +67,17 @@ enum ModbusConnection {
 MainWindow::MainWindow(QWidget *parent)
     : QMainWindow(parent)
     , ui(new Ui::MainWindow)
-    , modbusDevice(nullptr)
 {
     ui->setupUi(this);
     setupWidgetContainers();
 
 #if QT_CONFIG(modbus_serialport)
     ui->connectType->setCurrentIndex(0);
-    on_connectType_currentIndexChanged(0);
+    onCurrentConnectTypeChanged(0);
 #else
     // lock out the serial port option
     ui->connectType->setCurrentIndex(1);
-    on_connectType_currentIndexChanged(1);
+    onCurrentConnectTypeChanged(1);
     ui->connectType->setEnabled(false);
 #endif
 
@@ -102,16 +101,20 @@ void MainWindow::initActions()
     ui->actionExit->setEnabled(true);
     ui->actionOptions->setEnabled(true);
 
+    connect(ui->connectButton, &QPushButton::clicked,
+            this, &MainWindow::onConnectButtonClicked);
     connect(ui->actionConnect, &QAction::triggered,
-            this, &MainWindow::on_connectButton_clicked);
+            this, &MainWindow::onConnectButtonClicked);
     connect(ui->actionDisconnect, &QAction::triggered,
-            this, &MainWindow::on_connectButton_clicked);
+            this, &MainWindow::onConnectButtonClicked);
+    connect(ui->connectType, QOverload<int>::of(&QComboBox::currentIndexChanged),
+            this, &MainWindow::onCurrentConnectTypeChanged);
 
     connect(ui->actionExit, &QAction::triggered, this, &QMainWindow::close);
     connect(ui->actionOptions, &QAction::triggered, m_settingsDialog, &QDialog::show);
 }
 
-void MainWindow::on_connectType_currentIndexChanged(int index)
+void MainWindow::onCurrentConnectTypeChanged(int index)
 {
     if (modbusDevice) {
         modbusDevice->disconnect();
@@ -119,7 +122,7 @@ void MainWindow::on_connectType_currentIndexChanged(int index)
         modbusDevice = nullptr;
     }
 
-    ModbusConnection type = static_cast<ModbusConnection> (index);
+    auto type = static_cast<ModbusConnection>(index);
     if (type == Serial) {
 #if QT_CONFIG(modbus_serialport)
         modbusDevice = new QModbusRtuSerialSlave(this);
@@ -176,14 +179,14 @@ void MainWindow::handleDeviceError(QModbusDevice::Error newError)
     statusBar()->showMessage(modbusDevice->errorString(), 5000);
 }
 
-void MainWindow::on_connectButton_clicked()
+void MainWindow::onConnectButtonClicked()
 {
     bool intendToConnect = (modbusDevice->state() == QModbusDevice::UnconnectedState);
 
     statusBar()->clearMessage();
 
     if (intendToConnect) {
-        if (static_cast<ModbusConnection> (ui->connectType->currentIndex()) == Serial) {
+        if (static_cast<ModbusConnection>(ui->connectType->currentIndex()) == Serial) {
             modbusDevice->setConnectionParameter(QModbusDevice::SerialPortNameParameter,
                 ui->portEdit->text());
 #if QT_CONFIG(modbus_serialport)
@@ -244,7 +247,7 @@ void MainWindow::bitChanged(int id, QModbusDataUnit::RegisterType table, bool va
     if (!modbusDevice)
         return;
 
-    if (!modbusDevice->setData(table, id, value))
+    if (!modbusDevice->setData(table, quint16(id), value))
         statusBar()->showMessage(tr("Could not set data: ") + modbusDevice->errorString(), 5000);
 }
 
@@ -256,11 +259,11 @@ void MainWindow::setRegister(const QString &value)
     const QString objectName = QObject::sender()->objectName();
     if (registers.contains(objectName)) {
         bool ok = true;
-        const int id = QObject::sender()->property("ID").toInt();
+        const quint16 id = quint16(QObject::sender()->property("ID").toUInt());
         if (objectName.startsWith(QStringLiteral("inReg")))
-            ok = modbusDevice->setData(QModbusDataUnit::InputRegisters, id, value.toInt(&ok, 16));
+            ok = modbusDevice->setData(QModbusDataUnit::InputRegisters, id, value.toUShort(&ok, 16));
         else if (objectName.startsWith(QStringLiteral("holdReg")))
-            ok = modbusDevice->setData(QModbusDataUnit::HoldingRegisters, id, value.toInt(&ok, 16));
+            ok = modbusDevice->setData(QModbusDataUnit::HoldingRegisters, id, value.toUShort(&ok, 16));
 
         if (!ok)
             statusBar()->showMessage(tr("Could not set register: ") + modbusDevice->errorString(),
@@ -275,11 +278,11 @@ void MainWindow::updateWidgets(QModbusDataUnit::RegisterType table, int address,
         QString text;
         switch (table) {
         case QModbusDataUnit::Coils:
-            modbusDevice->data(QModbusDataUnit::Coils, address + i, &value);
+            modbusDevice->data(QModbusDataUnit::Coils, quint16(address + i), &value);
             coilButtons.button(address + i)->setChecked(value);
             break;
         case QModbusDataUnit::HoldingRegisters:
-            modbusDevice->data(QModbusDataUnit::HoldingRegisters, address + i, &value);
+            modbusDevice->data(QModbusDataUnit::HoldingRegisters, quint16(address + i), &value);
             registers.value(QStringLiteral("holdReg_%1").arg(address + i))->setText(text
                 .setNum(value, 16));
             break;
@@ -296,10 +299,10 @@ void MainWindow::setupDeviceData()
     if (!modbusDevice)
         return;
 
-    for (int i = 0; i < coilButtons.buttons().count(); ++i)
+    for (quint16 i = 0; i < coilButtons.buttons().count(); ++i)
         modbusDevice->setData(QModbusDataUnit::Coils, i, coilButtons.button(i)->isChecked());
 
-    for (int i = 0; i < discreteButtons.buttons().count(); ++i) {
+    for (quint16 i = 0; i < discreteButtons.buttons().count(); ++i) {
         modbusDevice->setData(QModbusDataUnit::DiscreteInputs, i,
             discreteButtons.button(i)->isChecked());
     }
@@ -307,11 +310,11 @@ void MainWindow::setupDeviceData()
     bool ok;
     for (QLineEdit *widget : qAsConst(registers)) {
         if (widget->objectName().startsWith(QStringLiteral("inReg"))) {
-            modbusDevice->setData(QModbusDataUnit::InputRegisters, widget->property("ID").toInt(),
-                widget->text().toInt(&ok, 16));
+            modbusDevice->setData(QModbusDataUnit::InputRegisters, quint16(widget->property("ID").toUInt()),
+                widget->text().toUShort(&ok, 16));
         } else if (widget->objectName().startsWith(QStringLiteral("holdReg"))) {
-            modbusDevice->setData(QModbusDataUnit::HoldingRegisters, widget->property("ID").toInt(),
-                widget->text().toInt(&ok, 16));
+            modbusDevice->setData(QModbusDataUnit::HoldingRegisters, quint16(widget->property("ID").toUInt()),
+                widget->text().toUShort(&ok, 16));
         }
     }
 }
diff --git a/examples/serialbus/modbus/slave/mainwindow.h b/examples/serialbus/modbus/slave/mainwindow.h
index aec1e9d..e824649 100644
--- a/examples/serialbus/modbus/slave/mainwindow.h
+++ b/examples/serialbus/modbus/slave/mainwindow.h
@@ -77,7 +77,7 @@ public:
     ~MainWindow();
 
 private Q_SLOTS:
-    void on_connectButton_clicked();
+    void onConnectButtonClicked();
     void onStateChanged(int state);
 
     void coilChanged(int id);
@@ -87,7 +87,7 @@ private Q_SLOTS:
     void setRegister(const QString &value);
     void updateWidgets(QModbusDataUnit::RegisterType table, int address, int size);
 
-    void on_connectType_currentIndexChanged(int);
+    void onCurrentConnectTypeChanged(int);
 
     void handleDeviceError(QModbusDevice::Error newError);
 
@@ -96,13 +96,13 @@ private:
     void setupDeviceData();
     void setupWidgetContainers();
 
-    Ui::MainWindow *ui;
-    QModbusServer *modbusDevice;
+    Ui::MainWindow *ui = nullptr;
+    QModbusServer *modbusDevice = nullptr;
 
     QButtonGroup coilButtons;
     QButtonGroup discreteButtons;
     QHash<QString, QLineEdit *> registers;
-    SettingsDialog *m_settingsDialog;
+    SettingsDialog *m_settingsDialog = nullptr;
 };
 
 #endif // MAINWINDOW_H
diff --git a/examples/serialbus/modbus/slave/slave.pro b/examples/serialbus/modbus/slave/slave.pro
index aadef07..2e128c2 100644
--- a/examples/serialbus/modbus/slave/slave.pro
+++ b/examples/serialbus/modbus/slave/slave.pro
@@ -7,13 +7,18 @@ TARGET = modbusslave
 TEMPLATE = app
 CONFIG += c++11
 
-SOURCES += main.cpp\
-        mainwindow.cpp \
-        settingsdialog.cpp
+SOURCES += \
+    main.cpp \
+    mainwindow.cpp \
+    settingsdialog.cpp
 
-HEADERS  += mainwindow.h settingsdialog.h
+HEADERS += \
+    mainwindow.h \
+    settingsdialog.h
 
-FORMS    += mainwindow.ui settingsdialog.ui
+FORMS += \
+    mainwindow.ui \
+    settingsdialog.ui
 
 RESOURCES += slave.qrc