QProcess 不发出完成信号

Question

QProcess* p = new QProcess;
p->setProgram("ping");
p->setArguments(QStringList()<<"127.0.0.1");
connect(p, QOverload<int, QProcess::ExitStatus>::of(&QProcess::finished),
    [=](int exitCode, QProcess::ExitStatus exitStatus){
    qDebug()<<"finished";
});
connect(p, &QProcess::stateChanged,
    [=](QProcess::ProcessState state){
    qDebug()<<"stateChanged"<<state;
});
qDebug()<<p->startDetached();
qDebug()<<"startDetached";

as the above demo, I expect output finished after ping is done. but it didn't, even stateChanged didn't emit.

(BTW, I think I have plan B to implement this by using qtconcurrent)

Answer 1

https://doc.qt.io/qt-5/qprocess.html

QString hostName = "127.0.0.1";

proc = new QProcess();
connect(p, QOverload<int, QProcess::ExitStatus>::of(&QProcess::finished),
    [=](int exitCode, QProcess::ExitStatus exitStatus){
    qDebug()<<"finished";
});
connect(p, &QProcess::stateChanged,
    [=](QProcess::ProcessState state){
    qDebug()<<"stateChanged"<<state;
});
proc->start("ping", QStringList() << QString(hostName));