Update code style, fix compiler warnings

- Use nullptr instead of NULL for better warnings in case of mistakes
- Get rid of VLAs which are not in C++11 actually
- Fix implicit signed <-> unsigned mismatches by adding checks and casts

10 files changed, 100 insertions, 97 deletions

diff --git a/src/server/connectionframe/connectionframe.cpp b/src/server/connectionframe/connectionframe.cpp
index 875e031..e8d8349 100644
--- a/src/server/connectionframe/connectionframe.cpp
+++ b/src/server/connectionframe/connectionframe.cpp
@@ -58,7 +58,7 @@ static QString style_disconnected(
 		QGroupBox { background-color: #7F7F7F; margin: 1px; border-radius: 4px}"
 );
 
-static QIcon *term = NULL, *cam = NULL, *eye = NULL, *lock = NULL;
+static QIcon *term = nullptr, *cam = nullptr, *eye = nullptr, *lock = nullptr;
 
 bool ConnectionFrame::paintDisabled = false;
 
@@ -69,13 +69,13 @@ bool ConnectionFrame::paintDisabled = false;
  * @param height
  */
 ConnectionFrame::ConnectionFrame(MainWindow* main, QWidget *parent, bool fromRoomplan) :
-	QGroupBox(parent), _client(NULL), _timerId(0), _timerCounter(0), _isSelected(false), _isTutor(false),
+	QGroupBox(parent), _client(nullptr), _timerId(0), _timerCounter(0), _isSelected(false), _isTutor(false),
 	_isFromRoomplan(fromRoomplan), _mainWindow(main)
 {
 
 	//defines the ui-stuff
 	// load icons first
-	if (term == NULL) {
+	if (term == nullptr) {
 		term = new QIcon(":terminal");
 		cam = new QIcon(":cf_cam");
 		eye = new QIcon(":cf_eye");
@@ -88,7 +88,7 @@ ConnectionFrame::ConnectionFrame(MainWindow* main, QWidget *parent, bool fromRoo
 	_mainLayout->setAlignment(Qt::AlignHCenter);
 	this->setStyleSheet(style_student);
 
-	_iconLayout = new QBoxLayout(QBoxLayout::RightToLeft, NULL);
+	_iconLayout = new QBoxLayout(QBoxLayout::RightToLeft, nullptr);
 	_iconLayout->setSpacing(1);
 	_iconLayout->setMargin(3);
 
@@ -124,7 +124,7 @@ ConnectionFrame::ConnectionFrame(MainWindow* main, QWidget *parent, bool fromRoo
 
 ConnectionFrame::~ConnectionFrame()
 {
-	if (_client != NULL) {
+	if (_client != nullptr) {
 		_client->deleteLater();
 	}
 	_iconLayout->deleteLater();
@@ -145,7 +145,7 @@ void ConnectionFrame::updateGeometry()
 {
 	const QRect rect = _mainWindow->calcFrameGeometry(this);
 	setGeometry(rect);
-	if (this->_client == NULL)
+	if (this->_client == nullptr)
 		showDefaultThumb();
 }
 
@@ -171,7 +171,7 @@ QLabel* ConnectionFrame::addIcon(const QIcon* icon)
  */
 void ConnectionFrame::assignClient(Client* client)
 {
-	assert(_client == NULL);
+	assert(_client == nullptr);
 	connect( client, SIGNAL(disconnected()), this, SLOT(onClientDisconnected()) );
 	connect( client, SIGNAL(thumbUpdated(Client*, const QImage&)), this, SLOT(onThumbUpdated(Client*, const QImage&)) );
 	connect( client, SIGNAL(vncServerStateChange(Client*)), this, SLOT(updateAppearance()));
@@ -206,7 +206,7 @@ void ConnectionFrame::calcDesiredThumbSize(const QSize &frameSize)
 void ConnectionFrame::updateLabels()
 {
 	_lblHostName->setText(_computerId);
-	if (_client == NULL) {
+	if (_client == nullptr) {
 		_lblUserName->setText(QString());
 		_lblUserName->hide();
 	} else {
@@ -331,7 +331,7 @@ void ConnectionFrame::paintEvent(QPaintEvent *event)
  */
 void ConnectionFrame::timerEvent(QTimerEvent* /* event */ )
 {
-	if (_client == NULL)
+	if (_client == nullptr)
 		return;
 	++_timerCounter;
 	if (_client->isActiveVncServer() && _timerCounter % 5 != 0)
@@ -357,7 +357,7 @@ void ConnectionFrame::setSelection(bool selected)
  */
 void ConnectionFrame::setTutor(bool b)
 {
-	if (_isTutor != b && _client != NULL)
+	if (_isTutor != b && _client != nullptr)
 		_client->setTutor(b);
 	_isTutor = b;
 	this->updateAppearance();
@@ -369,7 +369,7 @@ void ConnectionFrame::setTutor(bool b)
  */
 void ConnectionFrame::updateAppearance()
 {
-	if (_client == NULL) {
+	if (_client == nullptr) {
 		// Unconnected Frame
 		if (_isSelected) {
 			this->setStyleSheet(style_selectedStudent);
@@ -426,7 +426,7 @@ void ConnectionFrame::onClientDisconnected()
 		killTimer(_timerId);
 		_timerId = 0;
 	}
-	_client = NULL;
+	_client = nullptr;
 	updateLabels();
 	updateAppearance();
 	showDefaultThumb();
diff --git a/src/server/connectionframe/connectionframe.h b/src/server/connectionframe/connectionframe.h
index 898d97a..ba5f235 100644
--- a/src/server/connectionframe/connectionframe.h
+++ b/src/server/connectionframe/connectionframe.h
@@ -66,7 +66,7 @@ public:
 	inline bool isSelected() { return _isSelected; }
 
 	const QString& computerId() const { return _computerId; }
-	void setComputerId(QString computerId) { if (_client != NULL) return; _computerId = computerId; updateLabels(); }
+	void setComputerId(QString computerId) { if (_client != nullptr) return; _computerId = computerId; updateLabels(); }
 	Client* client() const { return _client; }
 
 	inline bool isTutor() { return _isTutor; }
diff --git a/src/server/mainwindow/mainwindow.cpp b/src/server/mainwindow/mainwindow.cpp
index 5daade4..dcf8973 100644
--- a/src/server/mainwindow/mainwindow.cpp
+++ b/src/server/mainwindow/mainwindow.cpp
@@ -190,7 +190,7 @@ void MainWindow::clientCountChanged()
 
 	for (auto it = _clientFrames.begin(); it != _clientFrames.end(); ++it) {
 		Client* c = (*it)->client();
-		if (c != NULL) {
+		if (c != nullptr) {
 			bool b = c->isExamMode();
 			examClientCount += b ? 1 : 0;
 			clientCount++;
@@ -262,7 +262,7 @@ int distance(QPointF a, QPointF b)
 QPoint MainWindow::closestFreeSlot(QPoint preferredPixels, ConnectionFrame* toIgnore)
 {
 	const bool pickFirstOne = ( preferredPixels == QPoint(-1, -1) );
-	if (!pickFirstOne && toIgnore != NULL) {
+	if (!pickFirstOne && toIgnore != nullptr) {
 		// Check if we're already in the desired location and skip all the checks
 		QPoint desired = QPoint(preferredPixels.x() / getTileWidthPx(), preferredPixels.y() / getTileHeightPx());
 		if (desired == toIgnore->getGridPosition()) {
@@ -270,8 +270,9 @@ QPoint MainWindow::closestFreeSlot(QPoint preferredPixels, ConnectionFrame* toIg
 		}
 	}
 	const QSize& clientSize = serverApp->getCurrentRoom()->clientSize;
-	bool grid[_tilesX][_tilesY];
-	memset(grid, 0, sizeof(bool) * _tilesX * _tilesY); /* set everything to false */
+#define GRID(X,Y) (grid[X * _tilesX + Y])
+	bool *grid = new bool[_tilesX * _tilesY];
+	memset(grid, 0, sizeof(bool) * size_t(_tilesX * _tilesY)); /* set everything to false */
 
 	/* fill grid */
 	for (auto  it = _clientFrames.begin(); it != _clientFrames.end(); ++it) {
@@ -282,7 +283,7 @@ QPoint MainWindow::closestFreeSlot(QPoint preferredPixels, ConnectionFrame* toIg
 
 		for (int x = p.x(); x < p.x() + clientSize.width(); x++) {
 			for (int y = p.y(); y < p.y() + clientSize.height(); y++) {
-				grid[x][y] = true;
+				GRID(x, y) = true;
 			}
 		}
 	}
@@ -295,7 +296,7 @@ QPoint MainWindow::closestFreeSlot(QPoint preferredPixels, ConnectionFrame* toIg
 			bool isFree = true;
 			for (int dx = 0; dx < clientSize.width(); dx++) {
 				for (int dy = 0; dy < clientSize.height(); dy++) {
-					if (grid[x + dx][y + dy]) {
+					if (GRID(x + dx, y + dy)) {
 						isFree = false;
 						goto endLoop; // double-break
 					}
@@ -311,6 +312,8 @@ endLoop: ;
 		}
 	}
 endSearch: ;
+#undef GRID
+	delete[] grid;
 	/* among all the free positions, find the closest */
 	int min_distance = 1000000;
 	QPoint bestPosition = QPoint(0, 0);
@@ -342,7 +345,7 @@ void MainWindow::placeFrameInFreeSlot(ConnectionFrame* frame, QPoint preferredPi
 ConnectionFrame* MainWindow::createFrame(const QString &computerId, const QPoint* gridPosition, bool fromRoomplan)
 {
 	ConnectionFrame *cf = new ConnectionFrame(this, ui->frmRoom, fromRoomplan);
-	if (gridPosition == NULL) {
+	if (gridPosition == nullptr) {
 		placeFrameInFreeSlot(cf);
 	} else {
 		cf->setGridPosition(*gridPosition);
@@ -378,47 +381,47 @@ void MainWindow::tellClientCurrentSituation(Client* client)
  * Returns connected client which belongs to given id.
  * Iterating over ConnectionFrames and comparing id to given id.
  * @param id
- * @return Client with given id, if not NULL.
+ * @return Client with given id, if not nullptr.
  */
 Client* MainWindow::getClientFromId(int id)
 {
 	for (QList<ConnectionFrame*>::iterator it(_clientFrames.begin()); it != _clientFrames.end(); ++it) {
-		if ((*it)->client() != NULL) {
+		if ((*it)->client() != nullptr) {
 			if ((*it)->client()->id() == id)
 				return (*it)->client();
 		}
 	}
-	return NULL;
+	return nullptr;
 }
 
 /***************************************************************************//**
  * Return the Frame, which is currently beeing Tutor.
  * Iterating over all ConnectionFrames, and looking for flag _isTutor.
  * @return Frame with flag _isTutor = true,
- * else NULL if no Tutor is available.
+ * else nullptr if no Tutor is available.
  */
 ConnectionFrame* MainWindow::getTutorFrame()
 {
 	for (QList<ConnectionFrame*>::iterator it(_clientFrames.begin()); it != _clientFrames.end(); ++it) {
-		if (((*it) != NULL) && ((*it)->isTutor()))
+		if (((*it) != nullptr) && ((*it)->isTutor()))
 			return (*it);
 	}
-	return NULL;
+	return nullptr;
 }
 
 /***************************************************************************//**
  * Return the Frame, which is currently selected by user.
  * Iterating over all ConnectionFrame and looking for flag _isSelected.
  * @return Frame with flag _isSelected = true,
- * else NULL if no frame is selected.
+ * else nullptr if no frame is selected.
  */
 ConnectionFrame* MainWindow::getSelectedFrame()
 {
 	for (QList<ConnectionFrame*>::iterator it(_clientFrames.begin()); it != _clientFrames.end(); ++it) {
-		if (((*it) != NULL) && ((*it)->isSelected()))
+		if (((*it) != nullptr) && ((*it)->isSelected()))
 			return (*it);
 	}
-	return NULL;
+	return nullptr;
 }
 
 /*
@@ -527,7 +530,7 @@ void MainWindow::resizeEvent(QResizeEvent* /* e */ )
 	}
 
 	/* update background image label */
-	if (_backgroundImage != NULL) {
+	if (_backgroundImage != nullptr) {
 		int w = ui->frmRoom->width() - 5; /* to make sure that we don't enlarge the window */
 		int h = ui->frmRoom->height() - 5;
 		ui->imageLabel->hide();
@@ -553,10 +556,10 @@ void MainWindow::unlockContextButtons()
 		(*it)->setEnabled(true);
 	}
 	/* and disable some again based on special rules */
-	if (getSelectedFrame()->client() != NULL) {
+	if (getSelectedFrame()->client() != nullptr) {
 		ui->action_DeleteClient->setEnabled(false);
 	}
-	if (getSelectedFrame()->client() == NULL) {
+	if (getSelectedFrame()->client() == nullptr) {
 		ui->action_SetAsTutor->setEnabled(false);
 		ui->action_StudentToTutorExclusive->setEnabled(false);
 		ui->action_StudentToTutor->setEnabled(false);
@@ -583,7 +586,7 @@ void MainWindow::mouseReleaseEvent(QMouseEvent* e)
 	const QSize frame(ui->frmRoom->size());
 	if (frame.width() > pos.x() && frame.height() > pos.y()) {
 		lockContextButtons();
-		if (getSelectedFrame() != NULL) {
+		if (getSelectedFrame() != nullptr) {
 			getSelectedFrame()->setSelection(false);
 		}
 	}
@@ -598,13 +601,13 @@ void MainWindow::reset(bool lock)
 
 	// Unlock all clients
 	for (QList<ConnectionFrame*>::iterator it(_clientFrames.begin()); it != _clientFrames.end(); ++it)
-		if ((*it)->client() != NULL) {
+		if ((*it)->client() != nullptr) {
 			(*it)->client()->lockScreen(lock);
 			(*it)->client()->removeAttention();
 		}
 
 	// Stop server (Clients get stopped on ACK)
-	if (getClientFromId(_streamingSource) != NULL)
+	if (getClientFromId(_streamingSource) != nullptr)
 		getClientFromId(_streamingSource)->stopVncServer();
 }
 
@@ -623,7 +626,7 @@ void MainWindow::onPlaceFrame(ConnectionFrame* connectionFrame)
 	const QPoint preferredPixels = connectionFrame->pos();
 	placeFrameInFreeSlot(connectionFrame, preferredPixels);
 
-	//resizeEvent(NULL);
+	//resizeEvent(nullptr);
 }
 
 /***************************************************************************//**
@@ -638,7 +641,7 @@ void MainWindow::onFrameClicked(ConnectionFrame* frame)
 
 	// If another frame has been selected, unselect it
 	// Set the ui selected and set a new reference
-	if (getSelectedFrame() != NULL) {
+	if (getSelectedFrame() != nullptr) {
 		getSelectedFrame()->setSelection(false);
 	}
 	frame->setSelection(true);
@@ -698,14 +701,14 @@ void MainWindow::startVncServerIfNecessary(int from)
 	Client* ns = getClientFromId(from);
 
 	// if there is a server running which is not "from" stop it.
-	if (os != NULL && _streamingSource != from)
+	if (os != nullptr && _streamingSource != from)
 		os->stopVncServer();
 
 	// Set new streaming source
 	_streamingSource = from;
 
 	// If streaming source is already active avoid a restart
-	if (ns != NULL) {
+	if (ns != nullptr) {
 		if (ns->isActiveVncServer()) {
 			this->onVncServerStateChange(ns);
 		} else { // Could not take shortcut, (re)start VNC server on source
@@ -737,11 +740,11 @@ void MainWindow::onReloadRoomCancel()
 void MainWindow::reloadCurrentRoom()
 {
 	/* delete old image */
-	if (_backgroundImage != NULL) {delete _backgroundImage; }
-	_backgroundImage = NULL;
+	if (_backgroundImage != nullptr) {delete _backgroundImage; }
+	_backgroundImage = nullptr;
 
 	const Room *room = serverApp->getCurrentRoom();
-	if (room != NULL) {
+	if (room != nullptr) {
 		/* set tiles */
 		_tilesX = room->gridSize.width();
 		_tilesY = room->gridSize.height();
@@ -756,7 +759,7 @@ void MainWindow::reloadCurrentRoom()
 			onPlaceFrame(cf);
 			if (computerId == room->tutorIP) {
 				qDebug() << "set computer with id " << computerId << " as tutor per configuration";
-				if (getTutorFrame() != NULL) {
+				if (getTutorFrame() != nullptr) {
 					getTutorFrame()->setTutor(false);
 				}
 				cf->setTutor(true);
@@ -785,12 +788,12 @@ void MainWindow::reloadCurrentRoom()
 	}
 
 	/* and force a resize event (this scales the image)  */
-	resizeEvent(NULL);
+	resizeEvent(nullptr);
 }
 
 void MainWindow::onReloadRoomOk()
 {
-	if (_reloadWindow->ui->roomList->currentItem() == NULL) {
+	if (_reloadWindow->ui->roomList->currentItem() == nullptr) {
 		QMessageBox::critical(this, "Warning", tr("No item selected, please select room!"), 0, 1);
 		return;
 	}
@@ -855,9 +858,9 @@ void MainWindow::onButtonTutorToAll()
 {
 	ui->action_Lock->setChecked(false);
 
-	if (getTutorFrame() == NULL)
+	if (getTutorFrame() == nullptr)
 		QMessageBox::critical(this, tr("Projection"), sStrTutorNdef);
-	else if (getTutorFrame()->client() == NULL)
+	else if (getTutorFrame()->client() == nullptr)
 		QMessageBox::critical(this, tr("Projection"), sStrTutorOffline);
 	else if (_clientFrames.size() == 1)
 		QMessageBox::critical(this, tr("Projection"), sStrNoDestAv);
@@ -870,7 +873,7 @@ void MainWindow::onButtonTutorToAll()
 
 		// Set all clients as watchers of tutor. Except for the tutors desired source, which hase to be none
 		for (QList<ConnectionFrame*>::iterator it(_clientFrames.begin()); it != _clientFrames.end(); ++it)
-			if ((*it)->client() != NULL)
+			if ((*it)->client() != nullptr)
 				(*it)->client()->setDesiredProjectionSource((*it)->client() == getTutorFrame()->client() ? NO_SOURCE : getTutorFrame()->client()->id());
 
 		disableButtons();
@@ -887,21 +890,21 @@ void MainWindow::onButtonTutorToStudent()
 {
 	ui->action_Lock->setChecked(false);
 
-	if (getSelectedFrame() == NULL)
+	if (getSelectedFrame() == nullptr)
 		QMessageBox::critical(this, tr("Projection"), sStrDestNdef);
-	else if (getTutorFrame() == NULL)
+	else if (getTutorFrame() == nullptr)
 		QMessageBox::critical(this, tr("Projection"), sStrTutorNdef);
 	else if (getSelectedFrame() == getTutorFrame())
 		QMessageBox::critical(this, tr("Projection"), sStrSourceDestSame);
-	else if (getSelectedFrame()->client() == NULL)
+	else if (getSelectedFrame()->client() == nullptr)
 		QMessageBox::critical(this, tr("Projection"), sStrDestOffline);
-	else if (getTutorFrame()->client() == NULL)
+	else if (getTutorFrame()->client() == nullptr)
 		QMessageBox::critical(this, tr("Projection"), sStrTutorOffline);
 	else {
 		// If this is the first call in this mode clear the watchers
 		if (_mode != Mode::Multicast) {
 			for (QList<ConnectionFrame*>::iterator it(_clientFrames.begin()); it != _clientFrames.end(); ++it)
-				if ((*it)->client() != NULL)
+				if ((*it)->client() != nullptr)
 					(*it)->client()->setDesiredProjectionSource(NO_SOURCE);
 		}
 
@@ -925,15 +928,15 @@ void MainWindow::onButtonStudentToTutor()
 {
 	ui->action_Lock->setChecked(false);
 
-	if (getSelectedFrame() == NULL)
+	if (getSelectedFrame() == nullptr)
 		QMessageBox::critical(this, tr("Projection"), sStrSourceNdef);
-	else if (getTutorFrame() == NULL)
+	else if (getTutorFrame() == nullptr)
 		QMessageBox::critical(this, tr("Projection"), sStrTutorNdef);
 	else if (getTutorFrame() == getSelectedFrame())
 		QMessageBox::critical(this, tr("Projection"), sStrSourceDestSame);
-	else if (getSelectedFrame()->client() == NULL)
+	else if (getSelectedFrame()->client() == nullptr)
 		QMessageBox::critical(this, tr("Projection"), sStrSourceOffline);
-	else if (getTutorFrame()->client() == NULL)
+	else if (getTutorFrame()->client() == nullptr)
 		QMessageBox::critical(this, tr("Projection"), sStrTutorOffline);
 	else {
 		// If this is not the first run in this mode and the current source is selected, stop the streaming.
@@ -946,7 +949,7 @@ void MainWindow::onButtonStudentToTutor()
 
 		// Unset all clients desired sources. Except the tutors desired source, this has to be the selecteds frame
 		for (QList<ConnectionFrame*>::iterator it(_clientFrames.begin()); it != _clientFrames.end(); ++it)
-			if ((*it)->client() != NULL)
+			if ((*it)->client() != nullptr)
 				(*it)->client()->setDesiredProjectionSource(getTutorFrame()->client()->id() == (*it)->client()->id() ? getSelectedFrame()->client()->id() : NO_SOURCE);
 
 		disableButtons();
@@ -963,15 +966,15 @@ void MainWindow::onButtonStudentToTutorExclusive()
 {
 	ui->action_Lock->setChecked(false);
 
-	if (getSelectedFrame() == NULL)
+	if (getSelectedFrame() == nullptr)
 		QMessageBox::critical(this, tr("Projection"), sStrSourceNdef);
-	else if (getTutorFrame() == NULL)
+	else if (getTutorFrame() == nullptr)
 		QMessageBox::critical(this, tr("Projection"), sStrTutorNdef);
 	else if (getTutorFrame() == getSelectedFrame())
 		QMessageBox::critical(this, tr("Projection"), sStrSourceDestSame);
-	else if (getSelectedFrame()->client() == NULL)
+	else if (getSelectedFrame()->client() == nullptr)
 		QMessageBox::critical(this, tr("Projection"), sStrSourceOffline);
-	else if (getTutorFrame()->client() == NULL)
+	else if (getTutorFrame()->client() == nullptr)
 		QMessageBox::critical(this, tr("Projection"), sStrTutorOffline);
 	else {
 		Client *selectedClient = getSelectedFrame()->client();
@@ -986,7 +989,7 @@ void MainWindow::onButtonStudentToTutorExclusive()
 
 		// Unset all clients desired sources. Except the tutors desired source, this has to be the selecteds frame
 		for (QList<ConnectionFrame*>::iterator it(_clientFrames.begin()); it != _clientFrames.end(); ++it)
-			if ((*it)->client() != NULL)
+			if ((*it)->client() != nullptr)
 				(*it)->client()->setDesiredProjectionSource(tutorClient->id() == (*it)->client()->id() ? selectedClient->id() : NO_SOURCE);
 
 		disableButtons();
@@ -1022,14 +1025,14 @@ void MainWindow::onButtonLock(bool checked)
 void MainWindow::onButtonLockSingle()
 {
 	// If no frame is selected, warning.
-	if (getSelectedFrame() == NULL) {
+	if (getSelectedFrame() == nullptr) {
 		QMessageBox::critical(this, tr("Selection"), tr("No client is selected."));
 		return;
 	}
 	Client *client = getSelectedFrame()->client();
 
 	// If frame of inactive client has been selected unselect it
-	if (client == NULL) {
+	if (client == nullptr) {
 		QMessageBox::critical(this, tr("Selection"), tr("The selected client is not connected."));
 		return;
 	} else { // If selected client is locked, first unlock
@@ -1038,7 +1041,7 @@ void MainWindow::onButtonLockSingle()
 		if (!newState) {
 			// If no more clients are locked, reset button
 			for (QList<ConnectionFrame*>::iterator it(_clientFrames.begin()); it != _clientFrames.end(); ++it) {
-				if ((*it)->client() == NULL)
+				if ((*it)->client() == nullptr)
 					continue;
 				if ((*it)->client()->isLocked())
 					return;
@@ -1063,13 +1066,13 @@ void MainWindow::onButtonExit()
 void MainWindow::onButtonSetAsTutor()
 {
 	// If no frame is selected, warning.
-	if (getSelectedFrame() == NULL) {
+	if (getSelectedFrame() == nullptr) {
 		QMessageBox::critical(this, tr("Selection"), tr("No client is selected."));
 		return;
 	}
 
 	// If frame of inactive client has been selected unselect it
-	if (getSelectedFrame()->client() == NULL) {
+	if (getSelectedFrame()->client() == nullptr) {
 		QMessageBox::critical(this, tr("Selection"), tr("The selected client is not connected."));
 		return;
 	} else { // If selected client is locked, first unlock
@@ -1081,7 +1084,7 @@ void MainWindow::onButtonSetAsTutor()
 		return;
 
 	// Else unset the old and set the new tutor
-	if (getTutorFrame() != NULL) {
+	if (getTutorFrame() != nullptr) {
 		getTutorFrame()->setTutor(false);
 	}
 	getSelectedFrame()->setTutor(true);
@@ -1122,7 +1125,7 @@ void MainWindow::onClientAuthenticating(Client* client, ClientLogin* request)
 		inuse = false;
 		for (QList<ConnectionFrame*>::iterator it(_clientFrames.begin()); it != _clientFrames.end(); ++it) {
 			Client *c = (**it).client();
-			if (c == NULL)
+			if (c == nullptr)
 				continue;
 			if (!c->isAuthed())
 				continue;
@@ -1158,8 +1161,8 @@ void MainWindow::onClientAuthenticated(Client* client)
 	disconnect(client, SIGNAL(authenticated(Client*)), this, SLOT(onClientAuthenticated(Client*)));
 	connect(client, SIGNAL(vncServerStateChange(Client*)), this, SLOT(onVncServerStateChange(Client*)));
 	connect(client, SIGNAL(vncClientStateChange(Client*)), this, SLOT(onVncClientStateChange(Client*)));
-	ConnectionFrame *existing = NULL;
-	ConnectionFrame *cf = NULL;
+	ConnectionFrame *existing = nullptr;
+	ConnectionFrame *cf = nullptr;
 	for (QList<ConnectionFrame*>::iterator it(_clientFrames.begin()); it != _clientFrames.end(); ++it) {
 		if ((*it)->computerId() == client->ip()) {
 			existing = *it;
@@ -1167,7 +1170,7 @@ void MainWindow::onClientAuthenticated(Client* client)
 	}
 
 	// Clients ip already exists, but was not active.
-	if (existing != NULL) {
+	if (existing != nullptr) {
 		cf = existing;
 	} else {
 		cf = createFrame();
@@ -1193,7 +1196,7 @@ void MainWindow::onVncServerStateChange(Client* client)
 	if (client->isActiveVncServer()) {
 		// apply the desired projection sources
 		for (QList<ConnectionFrame*>::iterator it(_clientFrames.begin()); it != _clientFrames.end(); ++it)
-			if ( (*it)->client() != NULL) { // Ignore offline clients
+			if ( (*it)->client() != nullptr) { // Ignore offline clients
 				if ( (*it)->client()->desiredProjectionSource() == client->id() )
 					(*it)->client()->startVncClient(client);
 				else
@@ -1206,7 +1209,7 @@ void MainWindow::onVncServerStateChange(Client* client)
 	} else {
 		// VNC server stopped on some client or failed to start - reset local pending projection information
 		for (QList<ConnectionFrame*>::iterator it(_clientFrames.begin()); it != _clientFrames.end(); ++it) {
-			if ((*it)->client() != NULL) {
+			if ((*it)->client() != nullptr) {
 				if ((*it)->client()->desiredProjectionSource() == client->id()) {
 					(*it)->client()->setDesiredProjectionSource(NO_SOURCE);
 					(*it)->client()->stopVncClient();
@@ -1234,7 +1237,7 @@ void MainWindow::onVncServerStateChange(Client* client)
  */
 void MainWindow::onVncClientStateChange(Client* client)
 {
-	if (client != NULL) {
+	if (client != nullptr) {
 		// VNC Client stopped -> remove from watchers
 		if (!client->isActiveVncClient()) {
 			// Only unset a desired Projection source if it has not changed meanwhile
@@ -1252,7 +1255,7 @@ void MainWindow::onVncClientStateChange(Client* client)
 			 */
 			bool serverHasWatchers = false;
 			for (QList<ConnectionFrame*>::iterator it(_clientFrames.begin()); it != _clientFrames.end(); ++it)
-				if ((*it)->client() != NULL)
+				if ((*it)->client() != nullptr)
 					if ((*it)->client()->desiredProjectionSource() == client->projectionSource()) {
 						serverHasWatchers = true;
 						break;
@@ -1260,7 +1263,7 @@ void MainWindow::onVncClientStateChange(Client* client)
 
 			if ( !serverHasWatchers ) {
 				Client* c = getClientFromId(client->projectionSource());
-				if (c != NULL)
+				if (c != nullptr)
 					c->stopVncServer();
 			}
 		}
@@ -1296,11 +1299,11 @@ void MainWindow::onDeleteClient()
 {
 	// If no frame is selected, warning.
 	ConnectionFrame* frame = getSelectedFrame();
-	if (frame == NULL) {
+	if (frame == nullptr) {
 		QMessageBox::critical(this, tr("Selection"), tr("No client is selected."));
 		return;
 	}
-	if (frame->client() != NULL) {
+	if (frame->client() != nullptr) {
 		QMessageBox::critical(this, tr("Selection"), tr("This client is still connected."));
 		return;
 	}
diff --git a/src/server/mainwindow/mainwindow.h b/src/server/mainwindow/mainwindow.h
index 4e99747..43804a7 100644
--- a/src/server/mainwindow/mainwindow.h
+++ b/src/server/mainwindow/mainwindow.h
@@ -44,8 +44,8 @@ private:
 	Qt::ToolBarArea   _tbArea;
 	int  _tilesX;
 	int  _tilesY;
-	QImage* _backgroundImage = NULL;
-	QLabel* _examModeLabel = NULL;
+	QImage* _backgroundImage = nullptr;
+	QLabel* _examModeLabel = nullptr;
 
 
 	/* virtual columns to preserve the aspect ratio of the loaded room */
@@ -79,7 +79,7 @@ private:
 
 	QPoint closestFreeSlot(QPoint preferredPixels, ConnectionFrame* toIgnore);
 	void placeFrameInFreeSlot(ConnectionFrame* frame, QPoint preferred = QPoint(-1, -1));
-	ConnectionFrame* createFrame(const QString &computerId = QString(), const QPoint *gridPosition = NULL, bool fromRoomplan = false);
+	ConnectionFrame* createFrame(const QString &computerId = QString(), const QPoint *gridPosition = nullptr, bool fromRoomplan = false);
 	void savePosition(ConnectionFrame *cf);
 	void startVncServerIfNecessary(int from);
 	void tellClientCurrentSituation(Client* client);
diff --git a/src/server/net/certmanager.cpp b/src/server/net/certmanager.cpp
index a7df6cc..a503088 100644
--- a/src/server/net/certmanager.cpp
+++ b/src/server/net/certmanager.cpp
@@ -66,7 +66,7 @@ bool getPrivateKeyAndCert(const QString &name, QSslKey &key, QSslCertificate &ce
 
 void fatal()
 {
-	QMessageBox::critical(NULL, QCoreApplication::trUtf8("OpenSSL error", "CertManager"),
+	QMessageBox::critical(nullptr, QCoreApplication::trUtf8("OpenSSL error", "CertManager"),
 			QCoreApplication::trUtf8("Could not generate certificates for secure connections.\n"
 			"PVS will not work.\n\n"
 			"Press OK to quit.", "CertManager"));
diff --git a/src/server/net/client.cpp b/src/server/net/client.cpp
index c11cb63..9e96dec 100644
--- a/src/server/net/client.cpp
+++ b/src/server/net/client.cpp
@@ -19,7 +19,7 @@ int Client::_clientIdCounter = 0;
 /******************************************************************************/
 Client::Client(QTcpSocket* socket) : _socket(socket)
 {
-	assert(socket != NULL);
+	assert(socket != nullptr);
 	_authed = 0;
 	_projectionSource = 0;
 	_desiredSource = 0;
diff --git a/src/server/net/listenserver.cpp b/src/server/net/listenserver.cpp
index 0a585c7..628b62d 100644
--- a/src/server/net/listenserver.cpp
+++ b/src/server/net/listenserver.cpp
@@ -31,7 +31,7 @@ ListenServer::~ListenServer()
 void ListenServer::newClientConnection()
 {
 	QTcpSocket* sock;
-	while ((sock = _server.nextPendingConnection()) != NULL) {
+	while ((sock = _server.nextPendingConnection()) != nullptr) {
 		Client* client = new Client(sock); // TODO: what happens with disconnected clients
 		emit newClient(client);
 	}
diff --git a/src/server/net/sslserver.cpp b/src/server/net/sslserver.cpp
index 0e0639e..c11f0ae 100644
--- a/src/server/net/sslserver.cpp
+++ b/src/server/net/sslserver.cpp
@@ -20,7 +20,7 @@
 #include "certmanager.h"
 #include <unistd.h>
 
-SslServer::SslServer() : QTcpServer(NULL)
+SslServer::SslServer() : QTcpServer(nullptr)
 {
 	_tmr = startTimer(5123);
 }
@@ -43,10 +43,10 @@ void SslServer::incomingConnection(qintptr socketDescriptor)
 		if (++certFails > 5) {
 			CertManager::fatal();
 		}
-		::close(socketDescriptor);
+		::close((int)socketDescriptor);
 		return;
 	}
-	QSslSocket *serverSocket = new QSslSocket(NULL);
+	QSslSocket *serverSocket = new QSslSocket(nullptr);
 	connect(serverSocket, SIGNAL(sslErrors(const QList<QSslError> &)), this, SLOT(sslErrors(const QList<QSslError> &)));
 	connect(serverSocket, SIGNAL(disconnected()), this, SLOT(sock_closed()));
 	connect(serverSocket, SIGNAL(error(QAbstractSocket::SocketError)), this, SLOT(sock_error(QAbstractSocket::SocketError)));
@@ -70,7 +70,7 @@ void SslServer::incomingConnection(qintptr socketDescriptor)
 	}
 }
 
-void SslServer::sslErrors(const QList<QSslError> &errors)
+void SslServer::sslErrors(const QList<QSslError>& /* errors */)
 {
 	/*
 	qDebug() << "Client caused sslErrors before connection:";
@@ -134,6 +134,6 @@ QTcpSocket* SslServer::nextPendingConnection()
 			return sock;
 		}
 	}
-	return NULL;
+	return nullptr;
 }
 
diff --git a/src/server/serverapp/serverapp.cpp b/src/server/serverapp/serverapp.cpp
index 7ee06e0..f680f89 100644
--- a/src/server/serverapp/serverapp.cpp
+++ b/src/server/serverapp/serverapp.cpp
@@ -7,7 +7,7 @@ static QSize minimalGridSize(const QMap<QString, QPoint>& clientPositions, QSize
 
 ServerApp::ServerApp(int& argc, char** argv)
 	: QApplication(argc, argv),
-		_mainWindow(NULL),
+		_mainWindow(nullptr),
 		_managerOnly(false),
 		_isExam(false)
 {
@@ -132,8 +132,8 @@ const Room* ServerApp::getCurrentRoom()
 	if (_rooms.contains(_currentRoom)) {
 		return _rooms[_currentRoom];
 	} else {
-		static Room* defaultRoom = NULL;
-		if (defaultRoom == NULL) {
+		static Room* defaultRoom = nullptr;
+		if (defaultRoom == nullptr) {
 			defaultRoom = new Room(QMap<QString,
 			                       QPoint>(), QSize(8, 6), QSize(1, 1), "", "");
 		}
diff --git a/src/server/util/platform/screensaver.cpp b/src/server/util/platform/screensaver.cpp
index efffba9..cdd6ee1 100644
--- a/src/server/util/platform/screensaver.cpp
+++ b/src/server/util/platform/screensaver.cpp
@@ -14,17 +14,17 @@
 
 namespace {
 
-	Display *display = NULL;
+	Display *display = nullptr;
 	bool extensionSupported = false;
 	bool dpmsSupported = false;
 
 	bool init()
 	{
-		if (display != NULL) {
+		if (display != nullptr) {
 			return true;
 		}
 		display = QX11Info::display();
-		if (display == NULL) {
+		if (display == nullptr) {
 			return false;
 		}
 #ifdef X11_Xscreensaver_FOUND