QLocalSocket to QLocalServer message being corrupted during transfer - c++

Question

I haven't been able to find a similar issue, so here goes:
I'm sending a QString from a QLocalSocket to a QLocalServer across two applications. The receiving (QLocalServer) application does receive the message, but it seems the encoding is completely wrong.
If I send a QString = "x" from the QLocalSocket (client), I'm getting a foreign (Chinese?) symbol in the QLocalServer. My code is literally copied from the Nokia Developer website
If I printout the message via QDebug, I get "??". If I fire it in a message box, Chinese characters are printed. I've tried re-encoding the received message to UTF-8, Latin1, etc., with no luck.
Code is as follows:
//Client
int main(int argc, char *argv[])
{
QLocalSocket * m_socket = new QLocalSocket();
m_socket->connectToServer("SomeServer");
if(m_socket->waitForConnected(1000))
{
//send a message to the server
QByteArray block;
QDataStream out(&block, QIODevice::WriteOnly);
out.setVersion(QDataStream::Qt_4_7);
out << "x";
out.device()->seek(0);
m_socket->write(block);
m_socket->flush();
QMessageBox box;
box.setText("mesage has been sent");
box.exec();
...
}
//Server - this is within a QMainWindow
void MainWindow::messageReceived()
{
QLocalSocket *clientConnection = m_pServer->nextPendingConnection();
while (clientConnection->bytesAvailable() < (int)sizeof(quint32))
clientConnection->waitForReadyRead();
connect(clientConnection, SIGNAL(disconnected()),
clientConnection, SLOT(deleteLater()));
QDataStream in(clientConnection);
in.setVersion(QDataStream::Qt_4_7);
if (clientConnection->bytesAvailable() < (int)sizeof(quint16)) {
return;
}
QString message;
in >> message;
QMessageBox box;
box.setText(QString(message));
box.exec();
}
Any help is highly appreciated.

Answer 1

The client is serializing a const char* while the server is deserializing a QString. These aren't compatible. The former literally writes the string bytes, the latter first encodes to UTF-16. So, I guess on the server side, the raw string data "fff" is being decoded into a QString as though it were UTF-16 data... perhaps resulting in character U+6666, 晦.
Try changing the client to also serialize a QString, i.e.
// client writes a QString
out << QString::fromLatin1("fff");
// server reads a QString
QString message;
in >> message;