Getting QProcess to send Signals...

ModelTech

I have created a QWizardPage class, which has the following code in its constructor:

    Process = new QProcess(this);
    connect(Process, SIGNAL(stateChanged(QProcess::ProcessState)), this, SLOT(onRunning(QProcess::ProcessState)));
    connect(Process, SIGNAL(readyReadStandardOutput()), this, SLOT(onOutput()));
    connect(Process, SIGNAL(readyReadStandardError()), this, SLOT(onError()));

I have overriden the QWizardPage::initializePage() function and the code of my version of this function includes the following line:

Process->startDetached(Command);

where Command is QString that represents what should be executed. I see that this execution does take place and it does produce some text on stdout. However, none of the signals QProcess::stateChanged(QProcess::ProcessState), QProcess::readyReadStandardOutput() and QProcess::readyReadStandardError() get triggered as the slots in my QWizardPage to which these signals are connected do not get executed when the Command is executed. Is there anything that I should do to activate the signalling or so?

SGaist

Hi,

startDetached is a static method thus it doesn't use the Process object at all. Use start if you want to get something from your process.

ModelTech

Great! That solved it. Wasn't aware that startDetached is static...

SGaist

Well, the method documentation as well as QProcess's list of static methods are pretty clear.

However, with Qt 5.10, there will be a new version of that method.