reading and writing to QProcess in Qt Console Application

Question

Noted: this appears to be a specific issue question but hopefully it can be edited for all to related to

I need to interact with a QProcess object.

Answer 1

Unfortunately I don't have all your code, so I made an example. I hope it helps you.

If I compare my code to yours, I think the problem could be you are not calling readAllStandardOutput() after writing or maybe you are not calling exec() in your main.cpp.

#include <QCoreApplication>
#include <QProcess>
#include <QDebug>

class MyProcess : public QProcess
{
    Q_OBJECT

public:
    MyProcess(QObject *parent = 0);
    ~MyProcess() {}

public slots:
    void myReadyRead();
    void myReadyReadStandardOutput();
};

MyProcess::MyProcess(QObject *parent)
{
    connect(this,SIGNAL(readyRead()),
            this,SLOT(myReadyRead()));
    connect(this,SIGNAL(readyReadStandardOutput()),
            this,SLOT(myReadyReadStandardOutput()));
}

void MyProcess::myReadyRead() {
    qDebug() << Q_FUNC_INFO;
}

void MyProcess::myReadyReadStandardOutput() {
    qDebug() << Q_FUNC_INFO;
    // Note we need to add \n (it's like pressing enter key)
    this->write(QString("myname" + QString("\n")).toLatin1());
    // Next line no required
    // qDebug() << this->readAll();
    qDebug() << this->readAllStandardOutput();

}

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    MyProcess *myProcess = new MyProcess();

    QString program = "/home/fran/code/myscript.sh";

    myProcess->start("/bin/sh", QStringList() << program);

    a.exec();
}

#include "main.moc"

Script to test the application:

echo "enter your name:"
read n
if [ ! -z "$n" ];
then
    echo "success"
    exit 0;
else
    echo "failed"
    exit 1;
fi