QProcess ReadAllStandardError() - qt

Question

I need to connect a QProcess to an error handler, but I'm unsure how to pass the error string to the slot. What's below compiles, but doesn't work.
QString MainWindow::RunProcess(QString cstring)
{
QProcess *process = new QProcess(this);
connect(process,SIGNAL(readyReadStandardError()),this,SLOT( adberror(process::ReadAllStandardError() ) ))
process->start(cstring);
}
void MainWindow::adberror(QString errtxt)
{
qDebug() << "error handler";
qDebug() << errtxt;
}
I can induce a a process error, but adberror() never triggers.
When run, in the Application Output pane I see:
QObject::connect: No such slot MainWindow::adberror(process::ReadAllStandardError() )
QObject::connect: (receiver name: 'MainWindow')
edit: this is Qt 5.6. I did a new qmake/clean.

Answer 1

you have two options
1- wait before reading the output
QString MainWindow::RunProcess(QString cstring)
{
QProcess process;
process.start(cstring);
process.waitForFinished();
QString str = process.readAllStandardOutput();
}
2- make you process a member variable and remove your 1st argument from adberror. So,
in RunProcess
connect(process,SIGNAL(readyReadStandardError()),this,SLOT(adberror()))
then in adberror
QString str = process->readAllStandardOutput();
note that in your code you have a problem since your signal and slot args don't to match .. Also, ReadAllStandardError is not going to be ready anyways !
Edit: more code for the 2nd solution
mainwindow.h
class MainWindow
{
private://methods
void adberror();
private://attributes
QProcess* process;
};
mainwindow.cpp
QString MainWindow::RunProcess(QString cstring)
{
process = new QProcess(this);
connect(process,SIGNAL(readyReadStandardError()),this,SLOT(adberror()));
connect(process, SIGNAL(finished(int)), process, SLOT(deleteLater()));
process->start(cstring);
}
void MainWindow::adberror()
{
QString str = process->readAllStandardOutput();
qDebug() << str;
}

Answer 2

To process the readyReadStandardError() signal you should define the slot as:
private slots:
void adberror();
and use it:
connect(process,SIGNAL(readyReadStandardError()),this,SLOT( adberror() ));
i.e. with no arguments. Keep child process as a field of your MainWindow class to read data when it will be available.