Pausing execution until a specific message on a socket is received?

Question

Is there some way to make a function pause it's execution until the socket receives a specific message? Using Signals + QEventLoop to wait doesn't work because while it can wait for signals, there isn't any way to get the data the signal emitted (or is there?).

Answer 1

You could connect to the following signal:

void QIODevice::readyRead() [signal]

Then, you would basically read the data and if it is the one you are looking for, you could set a boolean variable to true that is initially false. Your function would continue the execution only when the variable is true.

Make sure that the function paused is not sleeping in a sync manner too much, etc, without having a dedicated thread.

So, this would be one way of solving your task:

MySocketManager::MySocketManager(QObject *parent): QObject(parent)
{
    ...
    connect(m_mySocket, SIGNAL(readyRead()), SLOT(handleReadyRead()));
    ...
}

void MySocketManager::handleReadyRead()
{
    if (m_mySocket.readAll() == "myMessage")
        continue = true;
}

...

void myFunction()
{
    ...
    continue = false;
    qDebug() << "Pause";
    while (!continue) { ... }
    qDebug() << "Continue";
    ...
}

This is a tad simplication of the issue, but since you have not shown much effort other than asking for solution, this should get you started.