Terminating and restarting an external program in linux and windows

[jiveaxe]

void MainApp::recvQuit()
{
    QDataStream in(tcpSocket,QIODevice::ReadOnly);
    in.setVersion(QDataStream::Qt_4_0);
    QString string;
    in >> string;
    if(string == QString("quit")) {
        // Quit application.
        QCoreApplication::instance()->quit();
    }
}

void MainApp::recvQuit()
{
    QDataStream in(tcpSocket,QIODevice::ReadOnly);
    in.setVersion(QDataStream::Qt_4_0);
    QString string;
    in >> string;
    if(string == QString("quit")) {
        // Quit application.
        QCoreApplication::instance()->quit();
    }
}

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Is right connecting recvQuit() to QTcpServer::newConnection() signal?

In MainApp I haven't QTcpSocket object (only QTcpServer): I need to create one, right?

Thanks

[bender86]

Is right connecting recvQuit() to QTcpServer::newConnection() signal?

No, you should get new connection socket, and connect its readyRead signal to recvQuit.

In MainApp I haven't QTcpSocket object (only QTcpServer): I need to create one, right?

When QTcpServer::newConnection is emitted, you should do:

void MainApp::newConnectionSlot()
{
    // Loop on all incoming connections.
    while(tcpServer->hasPendingConnections()) {
        QTcpSocket *socket = tcpServer->nextPendingConnection();
        // Connect socket's signal, etc...
    }
}

void MainApp::newConnectionSlot()
{
    // Loop on all incoming connections.
    while(tcpServer->hasPendingConnections()) {
        QTcpSocket *socket = tcpServer->nextPendingConnection();
        // Connect socket's signal, etc...
    }
}

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[jiveaxe]

Hi,
finally the problem is solved thanks to bender86 last post. This is the final code (if it may be useful to somebody else):

class MainApp: public QDialog
{
	...
	private slots:
		void startUpdater();
		void readIncomingData();
		void newConnectionSlot();
		...
 
	private:
		QProcess *myProcess;
		QTcpServer *tcpServer;
		QTcpSocket *tcpSocket;
		...
};
 
MainApp::MainApp(QWidget *parent)
	:QDialog(parent)
{
	myProcess = 0;
 
	...
 
	tcpServer = new QTcpServer(this);
	if (!tcpServer->listen()) {
		QMessageBox::critical(this, tr("Server"),
							  tr("Unable to start the server: %1.")
							  .arg(tcpServer->errorString()));
		close();
		return;
	}
 
	connect(tcpServer, SIGNAL(newConnection()), this, SLOT(newConnectionSlot()));
 
	...
 
	connect(pushButton_1, SIGNAL(clicked()), this, SLOT(startUpdater()));
 
	...
}
 
void MainApp::startUpdater()
{
	QString program = "updater";
	QStringList args;
	args << port.toString();
 
	...
 
	myProcess = new QProcess(this);
	myProcess->startDetached(program, args);
}
 
void MainApp::newConnectionSlot()
{
	while(tcpServer->hasPendingConnections()) {
		tcpSocket = tcpServer->nextPendingConnection();
		connect(tcpSocket, SIGNAL(readyRead()), this, SLOT(readIncomingData()));
	}
}
 
void MainApp::readIncomingData()
{
	...
 
	QDataStream in(tcpSocket);
	in.setVersion(QDataStream::Qt_4_0);
	QString string;
	in >> string;
	if(string == QString("quit")) {
        // Quit application.
		QCoreApplication::instance()->quit();
	}
}

class MainApp: public QDialog
{
	...
	private slots:
		void startUpdater();
		void readIncomingData();
		void newConnectionSlot();
		...

	private:
		QProcess *myProcess;
		QTcpServer *tcpServer;
		QTcpSocket *tcpSocket;
		...
};

MainApp::MainApp(QWidget *parent)
	:QDialog(parent)
{
	myProcess = 0;

	...

	tcpServer = new QTcpServer(this);
	if (!tcpServer->listen()) {
		QMessageBox::critical(this, tr("Server"),
							  tr("Unable to start the server: %1.")
							  .arg(tcpServer->errorString()));
		close();
		return;
	}

	connect(tcpServer, SIGNAL(newConnection()), this, SLOT(newConnectionSlot()));

	...

	connect(pushButton_1, SIGNAL(clicked()), this, SLOT(startUpdater()));

	...
}

void MainApp::startUpdater()
{
	QString program = "updater";
	QStringList args;
	args << port.toString();

	...

	myProcess = new QProcess(this);
	myProcess->startDetached(program, args);
}

void MainApp::newConnectionSlot()
{
	while(tcpServer->hasPendingConnections()) {
		tcpSocket = tcpServer->nextPendingConnection();
		connect(tcpSocket, SIGNAL(readyRead()), this, SLOT(readIncomingData()));
	}
}

void MainApp::readIncomingData()
{
	...

	QDataStream in(tcpSocket);
	in.setVersion(QDataStream::Qt_4_0);
	QString string;
	in >> string;
	if(string == QString("quit")) {
        // Quit application.
		QCoreApplication::instance()->quit();
	}
}

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class Updater: public QDialog
{
	...
	private slots:
		void sendQuitCommand();
		...
 
	private:
		QTcpSocket *tcpSocket;
		...
};
 
Updater::Updater(char *p, QWidget *parent)
	:QDialog(parent)
{
	port = p;
 
	...
 
	tcpSocket = new QTcpSocket(this);
	tcpSocket->connectToHost("localhost", port.toInt());
 
	...
}
 
void Updater::sendQuitCommand()
{
	QDataStream out(tcpSocket);
	out.setVersion(QDataStream::Qt_4_0);
	out << QString("quit");
	tcpSocket->disconnectFromHost();
}

class Updater: public QDialog
{
	...
	private slots:
		void sendQuitCommand();
		...

	private:
		QTcpSocket *tcpSocket;
		...
};

Updater::Updater(char *p, QWidget *parent)
	:QDialog(parent)
{
	port = p;

	...

	tcpSocket = new QTcpSocket(this);
	tcpSocket->connectToHost("localhost", port.toInt());

	...
}

void Updater::sendQuitCommand()
{
	QDataStream out(tcpSocket);
	out.setVersion(QDataStream::Qt_4_0);
	out << QString("quit");
	tcpSocket->disconnectFromHost();
}

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Regards