Run external program

aminemaar

Hi,
I want to run external application in my Qtquick application,
I used this code but it's not working

QProcess*   process = new QProcess();
QString program = "C:\\WTB\\Serveur\\svr.exe";
process->start(program);

mrjj

Hi
Hook up error handler and see what it says.

connect(process , &QProcess::errorOccurred, [=](QProcess::ProcessError error) 
{ 
    qDebug() << "error enum val = " << error << endl; 
});

Pablo J. Rogina

@aminemaar said in Run external program:

my Qtquick application

but you're showing C++ code, am I missing something?

Cobra91151

Hello! To start the external program, you can also check the startDetached (https://doc.qt.io/qt-5/qprocess.html#startDetached) and execute (https://doc.qt.io/qt-5/qprocess.html#execute) methods. You can even use the static QProcess::startDetached("calc.exe"); method.

SGaist

@Cobra91151 The various detached methods won't help. Here @aminemaar needs to discover why its application is not running.

@aminemaar beside what @mrjj already wrote. What does your application do ? From the name it looks like some kind of network server ? In any case, did you also consider using the waitForStarted method ? This will allow you to know if the application started and in any case, check its status and potential error.

On a side note, doing it like that, you are leaking the QProcess object. How are you planning to handle it ?

Cobra91151

@SGaist

Yes, I agree. So, how about this:

Code:

QProcess *appProcess = new QProcess();
    connect(appProcess, &QProcess::started, [appProcess]() {
        qDebug() << "Started!";
        qDebug() << "PID: " << appProcess->processId();
        qDebug() << "Process state: " << appProcess->state();
    });
    connect(appProcess, qOverload<int, QProcess::ExitStatus>(&QProcess::finished), [appProcess](int exitCode, QProcess::ExitStatus exitStatus) {
        qDebug() << exitCode;
        qDebug() << exitStatus;
        appProcess->deleteLater(); //clear the QProcess object
    });
    appProcess->start("calc");

It will check the process state/pid, exit code and status and then delete the object using deleteLater() method.

Also @aminemaar can try the native Win API function combined with Qt:

HINSTANCE startApp(bool runAppAsAdmin, QString appPath, QString appArguments)
{
    HINSTANCE hResult;

    if (runAppAsAdmin) {
        hResult = ShellExecute(nullptr, L"runas", appPath.toStdWString().c_str(), appArguments.toStdWString().c_str(), nullptr, SW_SHOW);
    } else {
        hResult = ShellExecute(nullptr, nullptr, appPath.toStdWString().c_str(), appArguments.toStdWString().c_str(), nullptr, SW_SHOW);
    }

    return hResult;
}