QProcess write

shahriar25

Hi
I'm trying to run a external c++ file using QProcess in my app. this is the c++ source:

int main()
{
string s;
cout<<"enter s:";
cin>>s;
cout<<s;
}

I use a QTextEdit to show and get named Terminal this is what happens when the return key is pressed on my textedit:

void MainWindow::onTerminalReturnPressed()
{
QString text = Terminal->toPlainText();

process->write(QByteArray::fromStdString(text.toStdString()));
process->waitForBytesWritten();

}

and this is what happens when there is something to read from process:

void MainWindow::onProcessReadyRead()
{
Terminal->append(process->readAll());
}

when I run the app, "enter s" is shown in the textedit. when I enter anything and press return the text nothing happenes (the string doesn't get shown). what am I doing wrong?

SGaist

Hi,

You should rather use readAllStandardOutput.

On a side note, there's not need for these conversion from and to std::string. You can get a QByteArray from QString directly using either toUtf8 or toLatin1.

shahriar25

Hi Thank you @SGaist
I changed the code to show the standard output and the standard error.
The main problem was with the end lines. apparently std::cin recognizes \n as the end of input in linux.

kshegunov

@shahriar25 said:

apparently std::cin recognizes \n as the end of input in linux.

Same as windows, same as OSX. In text mode \n is end of line, that is where cin >> will stop reading.

shahriar25

Thank you kshegunov & SGaist. the problem is solved

Solved QProcess write