Problem using stdout in QProcess

vkonstantinov

I am a new in QT. need to catch the output from the process which I started.
What I am doing wrong?

Thank you.

@ QString program = "echo";
QStringList arguments;
arguments << "test >/dev/stdout";

 QProcess *myProcess = new QProcess(this);

 myProcess->start(program, arguments);
 myProcess->setReadChannel( QProcess::StandardOutput );
 char buff[1024];

  qint64 len = myProcess->readLine( buff, qint64(1024));
  int len = myProcess->readLine( buff, qint64(1024));
  printf(" buffer %s %d \n", buff, int(len));@

get nothing as result

andre

You don't give your process time to actually start doing something. Use the QProcess::readyRead() signal, and connect it to a slot where you do the actual reading.

tomma

Or just waitForFinished() after start().
Tricky part might be getting those arguments right

andre

[quote author="Tomma" date="1300440105"]Or just waitForFinished() after start().
Tricky part might be getting those arguments right[/quote]
I recommend against using the waitFor* methods in Qt if you can avoid them at all, especially if you are building GUI applications.

giesbert

[quote author="Andre" date="1300440589"]I recommend against using the waitFor* methods in Qt if you can avoid them at all, especially if you are building GUI applications.
[/quote]

Let's say it that way:

If you are building command line apps with have to wait, waitFor* makes sense.
If you build Gui, use signals.

Darryl DSouza

I agree with Gerolf. This way must work for you.

goetz

Be aware that you can not use shell input/output redirection (how should it work - there is no shell involved!). So this is wrong (in the sense of it does not do what you intended):

@
arguments << "test >/dev/stdout";
@

vkonstantinov

All, thank you very much. I am out of the office now, will test this soon. Sure it works.